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Commit | Line | Data |
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53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
ec2c5e43 | 2 | |
62cc1c55 | 3 | #include "sd-messages.h" |
beef6a5f | 4 | |
ec2c5e43 | 5 | #include "af-list.h" |
b5efdb8a | 6 | #include "alloc-util.h" |
f52e61da | 7 | #include "dns-domain.h" |
7cc6ed7b | 8 | #include "errno-list.h" |
c3fecddf | 9 | #include "errno-util.h" |
3ffd4af2 LP |
10 | #include "fd-util.h" |
11 | #include "random-util.h" | |
7778dfff | 12 | #include "resolved-dns-cache.h" |
3ffd4af2 | 13 | #include "resolved-dns-transaction.h" |
6016fcb0 | 14 | #include "resolved-dnstls.h" |
aedf00a2 | 15 | #include "resolved-llmnr.h" |
6016fcb0 | 16 | #include "string-table.h" |
5d67a7ae | 17 | |
b214dc0f | 18 | #define TRANSACTIONS_MAX 4096 |
dc349f5f | 19 | #define TRANSACTION_TCP_TIMEOUT_USEC (10U*USEC_PER_SEC) |
b214dc0f | 20 | |
dbc4661a MCO |
21 | /* After how much time to repeat classic DNS requests */ |
22 | #define DNS_TIMEOUT_USEC (SD_RESOLVED_QUERY_TIMEOUT_USEC / DNS_TRANSACTION_ATTEMPTS_MAX) | |
23 | ||
c61d2b44 LP |
24 | static void dns_transaction_reset_answer(DnsTransaction *t) { |
25 | assert(t); | |
26 | ||
27 | t->received = dns_packet_unref(t->received); | |
28 | t->answer = dns_answer_unref(t->answer); | |
29 | t->answer_rcode = 0; | |
30 | t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; | |
31 | t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID; | |
32 | t->answer_authenticated = false; | |
d3760be0 | 33 | t->answer_nsec_ttl = (uint32_t) -1; |
7cc6ed7b | 34 | t->answer_errno = 0; |
c61d2b44 LP |
35 | } |
36 | ||
c5b4f861 LP |
37 | static void dns_transaction_flush_dnssec_transactions(DnsTransaction *t) { |
38 | DnsTransaction *z; | |
39 | ||
40 | assert(t); | |
41 | ||
42 | while ((z = set_steal_first(t->dnssec_transactions))) { | |
43 | set_remove(z->notify_transactions, t); | |
35aa04e9 | 44 | set_remove(z->notify_transactions_done, t); |
c5b4f861 LP |
45 | dns_transaction_gc(z); |
46 | } | |
47 | } | |
48 | ||
f32f0e57 LP |
49 | static void dns_transaction_close_connection(DnsTransaction *t) { |
50 | assert(t); | |
51 | ||
b30bf55d LP |
52 | if (t->stream) { |
53 | /* Let's detach the stream from our transaction, in case something else keeps a reference to it. */ | |
98767d75 IT |
54 | LIST_REMOVE(transactions_by_stream, t->stream->transactions, t); |
55 | ||
56 | /* Remove packet in case it's still in the queue */ | |
57 | dns_packet_unref(ordered_set_remove(t->stream->write_queue, t->sent)); | |
58 | ||
b30bf55d LP |
59 | t->stream = dns_stream_unref(t->stream); |
60 | } | |
61 | ||
f32f0e57 LP |
62 | t->dns_udp_event_source = sd_event_source_unref(t->dns_udp_event_source); |
63 | t->dns_udp_fd = safe_close(t->dns_udp_fd); | |
64 | } | |
65 | ||
f535705a | 66 | static void dns_transaction_stop_timeout(DnsTransaction *t) { |
97cc656c LP |
67 | assert(t); |
68 | ||
69 | t->timeout_event_source = sd_event_source_unref(t->timeout_event_source); | |
97cc656c LP |
70 | } |
71 | ||
ec2c5e43 | 72 | DnsTransaction* dns_transaction_free(DnsTransaction *t) { |
801ad6a6 | 73 | DnsQueryCandidate *c; |
ec2c5e43 | 74 | DnsZoneItem *i; |
547973de | 75 | DnsTransaction *z; |
ec2c5e43 LP |
76 | |
77 | if (!t) | |
78 | return NULL; | |
79 | ||
51e399bc LP |
80 | log_debug("Freeing transaction %" PRIu16 ".", t->id); |
81 | ||
f32f0e57 | 82 | dns_transaction_close_connection(t); |
f535705a | 83 | dns_transaction_stop_timeout(t); |
ec2c5e43 | 84 | |
ec2c5e43 | 85 | dns_packet_unref(t->sent); |
c61d2b44 | 86 | dns_transaction_reset_answer(t); |
ec2c5e43 | 87 | |
8300ba21 | 88 | dns_server_unref(t->server); |
ec2c5e43 LP |
89 | |
90 | if (t->scope) { | |
f9ebb22a LP |
91 | hashmap_remove_value(t->scope->transactions_by_key, t->key, t); |
92 | LIST_REMOVE(transactions_by_scope, t->scope->transactions, t); | |
ec2c5e43 LP |
93 | |
94 | if (t->id != 0) | |
95 | hashmap_remove(t->scope->manager->dns_transactions, UINT_TO_PTR(t->id)); | |
96 | } | |
97 | ||
547973de | 98 | while ((c = set_steal_first(t->notify_query_candidates))) |
801ad6a6 | 99 | set_remove(c->transactions, t); |
547973de | 100 | set_free(t->notify_query_candidates); |
801ad6a6 | 101 | |
35aa04e9 LP |
102 | while ((c = set_steal_first(t->notify_query_candidates_done))) |
103 | set_remove(c->transactions, t); | |
104 | set_free(t->notify_query_candidates_done); | |
105 | ||
547973de | 106 | while ((i = set_steal_first(t->notify_zone_items))) |
ec2c5e43 | 107 | i->probe_transaction = NULL; |
547973de LP |
108 | set_free(t->notify_zone_items); |
109 | ||
35aa04e9 LP |
110 | while ((i = set_steal_first(t->notify_zone_items_done))) |
111 | i->probe_transaction = NULL; | |
112 | set_free(t->notify_zone_items_done); | |
113 | ||
547973de LP |
114 | while ((z = set_steal_first(t->notify_transactions))) |
115 | set_remove(z->dnssec_transactions, t); | |
116 | set_free(t->notify_transactions); | |
117 | ||
35aa04e9 LP |
118 | while ((z = set_steal_first(t->notify_transactions_done))) |
119 | set_remove(z->dnssec_transactions, t); | |
120 | set_free(t->notify_transactions_done); | |
121 | ||
c5b4f861 | 122 | dns_transaction_flush_dnssec_transactions(t); |
547973de LP |
123 | set_free(t->dnssec_transactions); |
124 | ||
125 | dns_answer_unref(t->validated_keys); | |
97cc656c | 126 | dns_resource_key_unref(t->key); |
97cc656c | 127 | |
6b430fdb | 128 | return mfree(t); |
ec2c5e43 LP |
129 | } |
130 | ||
131 | DEFINE_TRIVIAL_CLEANUP_FUNC(DnsTransaction*, dns_transaction_free); | |
132 | ||
51e399bc | 133 | bool dns_transaction_gc(DnsTransaction *t) { |
ec2c5e43 LP |
134 | assert(t); |
135 | ||
136 | if (t->block_gc > 0) | |
51e399bc | 137 | return true; |
ec2c5e43 | 138 | |
547973de | 139 | if (set_isempty(t->notify_query_candidates) && |
35aa04e9 | 140 | set_isempty(t->notify_query_candidates_done) && |
547973de | 141 | set_isempty(t->notify_zone_items) && |
35aa04e9 LP |
142 | set_isempty(t->notify_zone_items_done) && |
143 | set_isempty(t->notify_transactions) && | |
144 | set_isempty(t->notify_transactions_done)) { | |
ec2c5e43 | 145 | dns_transaction_free(t); |
51e399bc LP |
146 | return false; |
147 | } | |
148 | ||
149 | return true; | |
ec2c5e43 LP |
150 | } |
151 | ||
4dd15077 LP |
152 | static uint16_t pick_new_id(Manager *m) { |
153 | uint16_t new_id; | |
154 | ||
155 | /* Find a fresh, unused transaction id. Note that this loop is bounded because there's a limit on the number of | |
156 | * transactions, and it's much lower than the space of IDs. */ | |
157 | ||
158 | assert_cc(TRANSACTIONS_MAX < 0xFFFF); | |
159 | ||
160 | do | |
161 | random_bytes(&new_id, sizeof(new_id)); | |
162 | while (new_id == 0 || | |
163 | hashmap_get(m->dns_transactions, UINT_TO_PTR(new_id))); | |
164 | ||
165 | return new_id; | |
166 | } | |
167 | ||
f52e61da | 168 | int dns_transaction_new(DnsTransaction **ret, DnsScope *s, DnsResourceKey *key) { |
ec2c5e43 LP |
169 | _cleanup_(dns_transaction_freep) DnsTransaction *t = NULL; |
170 | int r; | |
171 | ||
172 | assert(ret); | |
173 | assert(s); | |
f52e61da | 174 | assert(key); |
ec2c5e43 | 175 | |
9eae2bf3 | 176 | /* Don't allow looking up invalid or pseudo RRs */ |
c463eb78 | 177 | if (!dns_type_is_valid_query(key->type)) |
9eae2bf3 | 178 | return -EINVAL; |
d0129ddb LP |
179 | if (dns_type_is_obsolete(key->type)) |
180 | return -EOPNOTSUPP; | |
9eae2bf3 LP |
181 | |
182 | /* We only support the IN class */ | |
4c701096 | 183 | if (!IN_SET(key->class, DNS_CLASS_IN, DNS_CLASS_ANY)) |
9eae2bf3 LP |
184 | return -EOPNOTSUPP; |
185 | ||
b214dc0f LP |
186 | if (hashmap_size(s->manager->dns_transactions) >= TRANSACTIONS_MAX) |
187 | return -EBUSY; | |
188 | ||
d5099efc | 189 | r = hashmap_ensure_allocated(&s->manager->dns_transactions, NULL); |
ec2c5e43 LP |
190 | if (r < 0) |
191 | return r; | |
192 | ||
f9ebb22a | 193 | r = hashmap_ensure_allocated(&s->transactions_by_key, &dns_resource_key_hash_ops); |
da0c630e LP |
194 | if (r < 0) |
195 | return r; | |
196 | ||
ec2c5e43 LP |
197 | t = new0(DnsTransaction, 1); |
198 | if (!t) | |
199 | return -ENOMEM; | |
200 | ||
4667e00a | 201 | t->dns_udp_fd = -1; |
c3bc53e6 | 202 | t->answer_source = _DNS_TRANSACTION_SOURCE_INVALID; |
019036a4 | 203 | t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; |
d3760be0 | 204 | t->answer_nsec_ttl = (uint32_t) -1; |
f52e61da | 205 | t->key = dns_resource_key_ref(key); |
274b8748 | 206 | t->current_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID; |
d001e0a3 | 207 | t->clamp_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID; |
ec2c5e43 | 208 | |
4dd15077 | 209 | t->id = pick_new_id(s->manager); |
ec2c5e43 LP |
210 | |
211 | r = hashmap_put(s->manager->dns_transactions, UINT_TO_PTR(t->id), t); | |
212 | if (r < 0) { | |
213 | t->id = 0; | |
214 | return r; | |
215 | } | |
216 | ||
f9ebb22a | 217 | r = hashmap_replace(s->transactions_by_key, t->key, t); |
da0c630e LP |
218 | if (r < 0) { |
219 | hashmap_remove(s->manager->dns_transactions, UINT_TO_PTR(t->id)); | |
220 | return r; | |
221 | } | |
222 | ||
f9ebb22a | 223 | LIST_PREPEND(transactions_by_scope, s->transactions, t); |
ec2c5e43 LP |
224 | t->scope = s; |
225 | ||
313cefa1 | 226 | s->manager->n_transactions_total++; |
a150ff5e | 227 | |
ec2c5e43 LP |
228 | if (ret) |
229 | *ret = t; | |
230 | ||
231 | t = NULL; | |
232 | ||
233 | return 0; | |
234 | } | |
235 | ||
4dd15077 LP |
236 | static void dns_transaction_shuffle_id(DnsTransaction *t) { |
237 | uint16_t new_id; | |
238 | assert(t); | |
239 | ||
240 | /* Pick a new ID for this transaction. */ | |
241 | ||
242 | new_id = pick_new_id(t->scope->manager); | |
243 | assert_se(hashmap_remove_and_put(t->scope->manager->dns_transactions, UINT_TO_PTR(t->id), UINT_TO_PTR(new_id), t) >= 0); | |
244 | ||
245 | log_debug("Transaction %" PRIu16 " is now %" PRIu16 ".", t->id, new_id); | |
246 | t->id = new_id; | |
247 | ||
248 | /* Make sure we generate a new packet with the new ID */ | |
249 | t->sent = dns_packet_unref(t->sent); | |
250 | } | |
251 | ||
ec2c5e43 | 252 | static void dns_transaction_tentative(DnsTransaction *t, DnsPacket *p) { |
2fb3034c | 253 | _cleanup_free_ char *pretty = NULL; |
202b76ae | 254 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
ec2c5e43 | 255 | DnsZoneItem *z; |
ec2c5e43 LP |
256 | |
257 | assert(t); | |
258 | assert(p); | |
259 | ||
260 | if (manager_our_packet(t->scope->manager, p) != 0) | |
261 | return; | |
262 | ||
164d025d | 263 | (void) in_addr_to_string(p->family, &p->sender, &pretty); |
2fb3034c | 264 | |
a5784c49 LP |
265 | log_debug("Transaction %" PRIu16 " for <%s> on scope %s on %s/%s got tentative packet from %s.", |
266 | t->id, | |
202b76ae | 267 | dns_resource_key_to_string(t->key, key_str, sizeof key_str), |
ec2c5e43 | 268 | dns_protocol_to_string(t->scope->protocol), |
6ff79f76 | 269 | t->scope->link ? t->scope->link->ifname : "*", |
202b76ae | 270 | af_to_name_short(t->scope->family), |
164d025d | 271 | strnull(pretty)); |
ec2c5e43 | 272 | |
a4076574 LP |
273 | /* RFC 4795, Section 4.1 says that the peer with the |
274 | * lexicographically smaller IP address loses */ | |
4d91eec4 LP |
275 | if (memcmp(&p->sender, &p->destination, FAMILY_ADDRESS_SIZE(p->family)) >= 0) { |
276 | log_debug("Peer has lexicographically larger IP address and thus lost in the conflict."); | |
a4076574 LP |
277 | return; |
278 | } | |
279 | ||
4d91eec4 | 280 | log_debug("We have the lexicographically larger IP address and thus lost in the conflict."); |
a4076574 | 281 | |
ec2c5e43 | 282 | t->block_gc++; |
35aa04e9 | 283 | |
547973de | 284 | while ((z = set_first(t->notify_zone_items))) { |
3ef64445 LP |
285 | /* First, make sure the zone item drops the reference |
286 | * to us */ | |
287 | dns_zone_item_probe_stop(z); | |
288 | ||
289 | /* Secondly, report this as conflict, so that we might | |
290 | * look for a different hostname */ | |
ec2c5e43 | 291 | dns_zone_item_conflict(z); |
3ef64445 | 292 | } |
ec2c5e43 LP |
293 | t->block_gc--; |
294 | ||
295 | dns_transaction_gc(t); | |
296 | } | |
297 | ||
298 | void dns_transaction_complete(DnsTransaction *t, DnsTransactionState state) { | |
801ad6a6 | 299 | DnsQueryCandidate *c; |
ec2c5e43 | 300 | DnsZoneItem *z; |
547973de | 301 | DnsTransaction *d; |
7cc6ed7b | 302 | const char *st; |
202b76ae | 303 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
ec2c5e43 LP |
304 | |
305 | assert(t); | |
547973de | 306 | assert(!DNS_TRANSACTION_IS_LIVE(state)); |
e56187ca | 307 | |
202b76ae ZJS |
308 | if (state == DNS_TRANSACTION_DNSSEC_FAILED) { |
309 | dns_resource_key_to_string(t->key, key_str, sizeof key_str); | |
310 | ||
f61dfddb | 311 | log_struct(LOG_NOTICE, |
2b044526 | 312 | "MESSAGE_ID=" SD_MESSAGE_DNSSEC_FAILURE_STR, |
202b76ae | 313 | LOG_MESSAGE("DNSSEC validation failed for question %s: %s", key_str, dnssec_result_to_string(t->answer_dnssec_result)), |
f61dfddb | 314 | "DNS_TRANSACTION=%" PRIu16, t->id, |
202b76ae | 315 | "DNS_QUESTION=%s", key_str, |
f61dfddb | 316 | "DNSSEC_RESULT=%s", dnssec_result_to_string(t->answer_dnssec_result), |
1e02e182 | 317 | "DNS_SERVER=%s", dns_server_string(t->server), |
a1230ff9 | 318 | "DNS_SERVER_FEATURE_LEVEL=%s", dns_server_feature_level_to_string(t->server->possible_feature_level)); |
202b76ae | 319 | } |
f61dfddb | 320 | |
ec2c5e43 LP |
321 | /* Note that this call might invalidate the query. Callers |
322 | * should hence not attempt to access the query or transaction | |
323 | * after calling this function. */ | |
324 | ||
7cc6ed7b LP |
325 | if (state == DNS_TRANSACTION_ERRNO) |
326 | st = errno_to_name(t->answer_errno); | |
327 | else | |
328 | st = dns_transaction_state_to_string(state); | |
329 | ||
a5784c49 LP |
330 | log_debug("Transaction %" PRIu16 " for <%s> on scope %s on %s/%s now complete with <%s> from %s (%s).", |
331 | t->id, | |
202b76ae | 332 | dns_resource_key_to_string(t->key, key_str, sizeof key_str), |
ec2c5e43 | 333 | dns_protocol_to_string(t->scope->protocol), |
6ff79f76 | 334 | t->scope->link ? t->scope->link->ifname : "*", |
202b76ae | 335 | af_to_name_short(t->scope->family), |
7cc6ed7b | 336 | st, |
a5784c49 LP |
337 | t->answer_source < 0 ? "none" : dns_transaction_source_to_string(t->answer_source), |
338 | t->answer_authenticated ? "authenticated" : "unsigned"); | |
ec2c5e43 LP |
339 | |
340 | t->state = state; | |
341 | ||
f32f0e57 | 342 | dns_transaction_close_connection(t); |
f535705a | 343 | dns_transaction_stop_timeout(t); |
ec2c5e43 LP |
344 | |
345 | /* Notify all queries that are interested, but make sure the | |
346 | * transaction isn't freed while we are still looking at it */ | |
347 | t->block_gc++; | |
f7014757 | 348 | |
35aa04e9 | 349 | SET_FOREACH_MOVE(c, t->notify_query_candidates_done, t->notify_query_candidates) |
547973de | 350 | dns_query_candidate_notify(c); |
35aa04e9 | 351 | SWAP_TWO(t->notify_query_candidates, t->notify_query_candidates_done); |
ec2c5e43 | 352 | |
35aa04e9 LP |
353 | SET_FOREACH_MOVE(z, t->notify_zone_items_done, t->notify_zone_items) |
354 | dns_zone_item_notify(z); | |
355 | SWAP_TWO(t->notify_zone_items, t->notify_zone_items_done); | |
8d67e72c | 356 | if (t->probing && t->state == DNS_TRANSACTION_ATTEMPTS_MAX_REACHED) |
1a63fc54 | 357 | (void) dns_scope_announce(t->scope, false); |
f7014757 | 358 | |
35aa04e9 LP |
359 | SET_FOREACH_MOVE(d, t->notify_transactions_done, t->notify_transactions) |
360 | dns_transaction_notify(d, t); | |
361 | SWAP_TWO(t->notify_transactions, t->notify_transactions_done); | |
f7014757 LP |
362 | |
363 | t->block_gc--; | |
ec2c5e43 LP |
364 | dns_transaction_gc(t); |
365 | } | |
366 | ||
519ef046 LP |
367 | static int dns_transaction_pick_server(DnsTransaction *t) { |
368 | DnsServer *server; | |
369 | ||
370 | assert(t); | |
371 | assert(t->scope->protocol == DNS_PROTOCOL_DNS); | |
372 | ||
d001e0a3 LP |
373 | /* Pick a DNS server and a feature level for it. */ |
374 | ||
519ef046 LP |
375 | server = dns_scope_get_dns_server(t->scope); |
376 | if (!server) | |
377 | return -ESRCH; | |
378 | ||
d001e0a3 LP |
379 | /* If we changed the server invalidate the feature level clamping, as the new server might have completely |
380 | * different properties. */ | |
381 | if (server != t->server) | |
382 | t->clamp_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID; | |
383 | ||
274b8748 | 384 | t->current_feature_level = dns_server_possible_feature_level(server); |
519ef046 | 385 | |
d001e0a3 LP |
386 | /* Clamp the feature level if that is requested. */ |
387 | if (t->clamp_feature_level != _DNS_SERVER_FEATURE_LEVEL_INVALID && | |
388 | t->current_feature_level > t->clamp_feature_level) | |
389 | t->current_feature_level = t->clamp_feature_level; | |
390 | ||
391 | log_debug("Using feature level %s for transaction %u.", dns_server_feature_level_to_string(t->current_feature_level), t->id); | |
392 | ||
519ef046 LP |
393 | if (server == t->server) |
394 | return 0; | |
395 | ||
396 | dns_server_unref(t->server); | |
397 | t->server = dns_server_ref(server); | |
398 | ||
44db02d0 LP |
399 | t->n_picked_servers ++; |
400 | ||
d001e0a3 LP |
401 | log_debug("Using DNS server %s for transaction %u.", dns_server_string(t->server), t->id); |
402 | ||
519ef046 LP |
403 | return 1; |
404 | } | |
405 | ||
d001e0a3 | 406 | static void dns_transaction_retry(DnsTransaction *t, bool next_server) { |
8d10d620 LP |
407 | int r; |
408 | ||
409 | assert(t); | |
410 | ||
411 | log_debug("Retrying transaction %" PRIu16 ".", t->id); | |
412 | ||
413 | /* Before we try again, switch to a new server. */ | |
d001e0a3 LP |
414 | if (next_server) |
415 | dns_scope_next_dns_server(t->scope); | |
8d10d620 LP |
416 | |
417 | r = dns_transaction_go(t); | |
7cc6ed7b LP |
418 | if (r < 0) { |
419 | t->answer_errno = -r; | |
420 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); | |
421 | } | |
8d10d620 LP |
422 | } |
423 | ||
c02cf2f4 | 424 | static int dns_transaction_maybe_restart(DnsTransaction *t) { |
5278bbfe LP |
425 | int r; |
426 | ||
c02cf2f4 LP |
427 | assert(t); |
428 | ||
5278bbfe LP |
429 | /* Returns > 0 if the transaction was restarted, 0 if not */ |
430 | ||
c02cf2f4 LP |
431 | if (!t->server) |
432 | return 0; | |
433 | ||
434 | if (t->current_feature_level <= dns_server_possible_feature_level(t->server)) | |
435 | return 0; | |
436 | ||
437 | /* The server's current feature level is lower than when we sent the original query. We learnt something from | |
438 | the response or possibly an auxiliary DNSSEC response that we didn't know before. We take that as reason to | |
439 | restart the whole transaction. This is a good idea to deal with servers that respond rubbish if we include | |
440 | OPT RR or DO bit. One of these cases is documented here, for example: | |
441 | https://open.nlnetlabs.nl/pipermail/dnssec-trigger/2014-November/000376.html */ | |
442 | ||
4dd15077 LP |
443 | log_debug("Server feature level is now lower than when we began our transaction. Restarting with new ID."); |
444 | dns_transaction_shuffle_id(t); | |
5278bbfe LP |
445 | |
446 | r = dns_transaction_go(t); | |
447 | if (r < 0) | |
448 | return r; | |
449 | ||
450 | return 1; | |
c02cf2f4 LP |
451 | } |
452 | ||
98767d75 IT |
453 | static void on_transaction_stream_error(DnsTransaction *t, int error) { |
454 | assert(t); | |
ec2c5e43 | 455 | |
b30bf55d | 456 | dns_transaction_close_connection(t); |
ec2c5e43 | 457 | |
a1a3f73a | 458 | if (ERRNO_IS_DISCONNECT(error)) { |
0791110f LP |
459 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR) { |
460 | /* If the LLMNR/TCP connection failed, the host doesn't support LLMNR, and we cannot answer the | |
461 | * question on this scope. */ | |
462 | dns_transaction_complete(t, DNS_TRANSACTION_NOT_FOUND); | |
daab72ea | 463 | return; |
0791110f LP |
464 | } |
465 | ||
d001e0a3 | 466 | dns_transaction_retry(t, true); |
daab72ea | 467 | return; |
ac720200 | 468 | } |
ec2c5e43 | 469 | if (error != 0) { |
7cc6ed7b LP |
470 | t->answer_errno = error; |
471 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); | |
ec2c5e43 | 472 | } |
98767d75 IT |
473 | } |
474 | ||
475 | static int dns_transaction_on_stream_packet(DnsTransaction *t, DnsPacket *p) { | |
476 | assert(t); | |
477 | assert(p); | |
478 | ||
479 | dns_transaction_close_connection(t); | |
ec2c5e43 | 480 | |
a4076574 | 481 | if (dns_packet_validate_reply(p) <= 0) { |
a20b9592 | 482 | log_debug("Invalid TCP reply packet."); |
a4076574 LP |
483 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); |
484 | return 0; | |
485 | } | |
486 | ||
487 | dns_scope_check_conflicts(t->scope, p); | |
488 | ||
ec2c5e43 LP |
489 | t->block_gc++; |
490 | dns_transaction_process_reply(t, p); | |
491 | t->block_gc--; | |
492 | ||
519ef046 LP |
493 | /* If the response wasn't useful, then complete the transition |
494 | * now. After all, we are the worst feature set now with TCP | |
495 | * sockets, and there's really no point in retrying. */ | |
ec2c5e43 LP |
496 | if (t->state == DNS_TRANSACTION_PENDING) |
497 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
598f44bd LP |
498 | else |
499 | dns_transaction_gc(t); | |
ec2c5e43 LP |
500 | |
501 | return 0; | |
502 | } | |
503 | ||
98767d75 | 504 | static int on_stream_complete(DnsStream *s, int error) { |
7172e4ee | 505 | assert(s); |
98767d75 IT |
506 | |
507 | if (ERRNO_IS_DISCONNECT(error) && s->protocol != DNS_PROTOCOL_LLMNR) { | |
98767d75 IT |
508 | log_debug_errno(error, "Connection failure for DNS TCP stream: %m"); |
509 | ||
510 | if (s->transactions) { | |
97d5d905 LP |
511 | DnsTransaction *t; |
512 | ||
98767d75 | 513 | t = s->transactions; |
3da3cdd5 | 514 | dns_server_packet_lost(t->server, IPPROTO_TCP, t->current_feature_level); |
98767d75 IT |
515 | } |
516 | } | |
517 | ||
97d5d905 LP |
518 | if (error != 0) { |
519 | DnsTransaction *t, *n; | |
520 | ||
521 | LIST_FOREACH_SAFE(transactions_by_stream, t, n, s->transactions) | |
98767d75 | 522 | on_transaction_stream_error(t, error); |
97d5d905 | 523 | } |
98767d75 | 524 | |
97d5d905 | 525 | return 0; |
98767d75 IT |
526 | } |
527 | ||
747a8a74 | 528 | static int on_stream_packet(DnsStream *s) { |
98767d75 | 529 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; |
98767d75 IT |
530 | DnsTransaction *t; |
531 | ||
aa337a5e LP |
532 | assert(s); |
533 | ||
98767d75 | 534 | /* Take ownership of packet to be able to receive new packets */ |
aa337a5e LP |
535 | p = dns_stream_take_read_packet(s); |
536 | assert(p); | |
98767d75 IT |
537 | |
538 | t = hashmap_get(s->manager->dns_transactions, UINT_TO_PTR(DNS_PACKET_ID(p))); | |
aa337a5e LP |
539 | if (t) |
540 | return dns_transaction_on_stream_packet(t, p); | |
98767d75 | 541 | |
8227cfa1 | 542 | /* Ignore incorrect transaction id as an old transaction can have been canceled. */ |
30f9e0bf | 543 | log_debug("Received unexpected TCP reply packet with id %" PRIu16 ", ignoring.", DNS_PACKET_ID(p)); |
aa337a5e | 544 | return 0; |
98767d75 IT |
545 | } |
546 | ||
ec962fba LP |
547 | static uint16_t dns_port_for_feature_level(DnsServerFeatureLevel level) { |
548 | return DNS_SERVER_FEATURE_LEVEL_IS_TLS(level) ? 853 : 53; | |
549 | } | |
550 | ||
98767d75 | 551 | static int dns_transaction_emit_tcp(DnsTransaction *t) { |
98767d75 | 552 | _cleanup_(dns_stream_unrefp) DnsStream *s = NULL; |
652ba568 | 553 | _cleanup_close_ int fd = -1; |
91ccab1e | 554 | union sockaddr_union sa; |
652ba568 | 555 | DnsStreamType type; |
ec2c5e43 LP |
556 | int r; |
557 | ||
558 | assert(t); | |
559 | ||
519ef046 | 560 | dns_transaction_close_connection(t); |
ec2c5e43 | 561 | |
106784eb | 562 | switch (t->scope->protocol) { |
519ef046 | 563 | |
106784eb | 564 | case DNS_PROTOCOL_DNS: |
519ef046 LP |
565 | r = dns_transaction_pick_server(t); |
566 | if (r < 0) | |
567 | return r; | |
568 | ||
92ec902a | 569 | if (!dns_server_dnssec_supported(t->server) && dns_type_is_dnssec(t->key->type)) |
91adc4db LP |
570 | return -EOPNOTSUPP; |
571 | ||
274b8748 | 572 | r = dns_server_adjust_opt(t->server, t->sent, t->current_feature_level); |
519ef046 LP |
573 | if (r < 0) |
574 | return r; | |
575 | ||
5d67a7ae | 576 | if (t->server->stream && (DNS_SERVER_FEATURE_LEVEL_IS_TLS(t->current_feature_level) == t->server->stream->encrypted)) |
98767d75 IT |
577 | s = dns_stream_ref(t->server->stream); |
578 | else | |
ec962fba | 579 | fd = dns_scope_socket_tcp(t->scope, AF_UNSPEC, NULL, t->server, dns_port_for_feature_level(t->current_feature_level), &sa); |
98767d75 | 580 | |
652ba568 | 581 | type = DNS_STREAM_LOOKUP; |
106784eb | 582 | break; |
ec2c5e43 | 583 | |
106784eb | 584 | case DNS_PROTOCOL_LLMNR: |
a8f6397f | 585 | /* When we already received a reply to this (but it was truncated), send to its sender address */ |
ec2c5e43 | 586 | if (t->received) |
91ccab1e | 587 | fd = dns_scope_socket_tcp(t->scope, t->received->family, &t->received->sender, NULL, t->received->sender_port, &sa); |
ec2c5e43 LP |
588 | else { |
589 | union in_addr_union address; | |
a7f7d1bd | 590 | int family = AF_UNSPEC; |
ec2c5e43 LP |
591 | |
592 | /* Otherwise, try to talk to the owner of a | |
593 | * the IP address, in case this is a reverse | |
594 | * PTR lookup */ | |
f52e61da | 595 | |
1c02e7ba | 596 | r = dns_name_address(dns_resource_key_name(t->key), &family, &address); |
ec2c5e43 LP |
597 | if (r < 0) |
598 | return r; | |
599 | if (r == 0) | |
600 | return -EINVAL; | |
9e08a6e0 | 601 | if (family != t->scope->family) |
9318cdd3 | 602 | return -ESRCH; |
ec2c5e43 | 603 | |
91ccab1e | 604 | fd = dns_scope_socket_tcp(t->scope, family, &address, NULL, LLMNR_PORT, &sa); |
ec2c5e43 | 605 | } |
106784eb | 606 | |
652ba568 | 607 | type = DNS_STREAM_LLMNR_SEND; |
106784eb DM |
608 | break; |
609 | ||
610 | default: | |
ec2c5e43 | 611 | return -EAFNOSUPPORT; |
106784eb | 612 | } |
ec2c5e43 | 613 | |
98767d75 IT |
614 | if (!s) { |
615 | if (fd < 0) | |
616 | return fd; | |
ec2c5e43 | 617 | |
652ba568 | 618 | r = dns_stream_new(t->scope->manager, &s, type, t->scope->protocol, fd, &sa); |
98767d75 IT |
619 | if (r < 0) |
620 | return r; | |
621 | ||
622 | fd = -1; | |
623 | ||
56ddbf10 | 624 | #if ENABLE_DNS_OVER_TLS |
199dda9c LP |
625 | if (t->scope->protocol == DNS_PROTOCOL_DNS && |
626 | DNS_SERVER_FEATURE_LEVEL_IS_TLS(t->current_feature_level)) { | |
627 | ||
b02a7e1a | 628 | assert(t->server); |
6016fcb0 | 629 | r = dnstls_stream_connect_tls(s, t->server); |
5d67a7ae IT |
630 | if (r < 0) |
631 | return r; | |
632 | } | |
633 | #endif | |
634 | ||
19feb28f | 635 | if (t->server) { |
904dcaf9 | 636 | dns_server_unref_stream(t->server); |
19feb28f | 637 | s->server = dns_server_ref(t->server); |
8227cfa1 | 638 | t->server->stream = dns_stream_ref(s); |
19feb28f IT |
639 | } |
640 | ||
98767d75 | 641 | s->complete = on_stream_complete; |
747a8a74 | 642 | s->on_packet = on_stream_packet; |
98767d75 IT |
643 | |
644 | /* The interface index is difficult to determine if we are | |
645 | * connecting to the local host, hence fill this in right away | |
646 | * instead of determining it from the socket */ | |
647 | s->ifindex = dns_scope_ifindex(t->scope); | |
648 | } | |
649 | ||
650 | t->stream = TAKE_PTR(s); | |
651 | LIST_PREPEND(transactions_by_stream, t->stream->transactions, t); | |
ec2c5e43 LP |
652 | |
653 | r = dns_stream_write_packet(t->stream, t->sent); | |
654 | if (r < 0) { | |
98767d75 | 655 | dns_transaction_close_connection(t); |
ec2c5e43 LP |
656 | return r; |
657 | } | |
658 | ||
519ef046 LP |
659 | dns_transaction_reset_answer(t); |
660 | ||
cbe4216d LP |
661 | t->tried_stream = true; |
662 | ||
ec2c5e43 LP |
663 | return 0; |
664 | } | |
665 | ||
547973de | 666 | static void dns_transaction_cache_answer(DnsTransaction *t) { |
547973de LP |
667 | assert(t); |
668 | ||
669 | /* For mDNS we cache whenever we get the packet, rather than | |
670 | * in each transaction. */ | |
671 | if (!IN_SET(t->scope->protocol, DNS_PROTOCOL_DNS, DNS_PROTOCOL_LLMNR)) | |
672 | return; | |
673 | ||
ceeddf79 | 674 | /* Caching disabled? */ |
37d7a7d9 | 675 | if (t->scope->manager->enable_cache == DNS_CACHE_MODE_NO) |
ceeddf79 MP |
676 | return; |
677 | ||
547973de LP |
678 | /* We never cache if this packet is from the local host, under |
679 | * the assumption that a locally running DNS server would | |
680 | * cache this anyway, and probably knows better when to flush | |
681 | * the cache then we could. */ | |
682 | if (!DNS_PACKET_SHALL_CACHE(t->received)) | |
683 | return; | |
684 | ||
547973de | 685 | dns_cache_put(&t->scope->cache, |
37d7a7d9 | 686 | t->scope->manager->enable_cache, |
547973de LP |
687 | t->key, |
688 | t->answer_rcode, | |
689 | t->answer, | |
547973de | 690 | t->answer_authenticated, |
d3760be0 | 691 | t->answer_nsec_ttl, |
547973de LP |
692 | 0, |
693 | t->received->family, | |
694 | &t->received->sender); | |
695 | } | |
696 | ||
105e1512 LP |
697 | static bool dns_transaction_dnssec_is_live(DnsTransaction *t) { |
698 | DnsTransaction *dt; | |
699 | Iterator i; | |
700 | ||
701 | assert(t); | |
702 | ||
703 | SET_FOREACH(dt, t->dnssec_transactions, i) | |
704 | if (DNS_TRANSACTION_IS_LIVE(dt->state)) | |
705 | return true; | |
706 | ||
707 | return false; | |
708 | } | |
709 | ||
942eb2e7 LP |
710 | static int dns_transaction_dnssec_ready(DnsTransaction *t) { |
711 | DnsTransaction *dt; | |
712 | Iterator i; | |
713 | ||
714 | assert(t); | |
715 | ||
716 | /* Checks whether the auxiliary DNSSEC transactions of our transaction have completed, or are still | |
717 | * ongoing. Returns 0, if we aren't ready for the DNSSEC validation, positive if we are. */ | |
718 | ||
719 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
720 | ||
721 | switch (dt->state) { | |
722 | ||
723 | case DNS_TRANSACTION_NULL: | |
724 | case DNS_TRANSACTION_PENDING: | |
725 | case DNS_TRANSACTION_VALIDATING: | |
726 | /* Still ongoing */ | |
727 | return 0; | |
728 | ||
729 | case DNS_TRANSACTION_RCODE_FAILURE: | |
b3c6b00a | 730 | if (!IN_SET(dt->answer_rcode, DNS_RCODE_NXDOMAIN, DNS_RCODE_SERVFAIL)) { |
942eb2e7 LP |
731 | log_debug("Auxiliary DNSSEC RR query failed with rcode=%s.", dns_rcode_to_string(dt->answer_rcode)); |
732 | goto fail; | |
733 | } | |
734 | ||
b3c6b00a | 735 | /* Fall-through: NXDOMAIN/SERVFAIL is good enough for us. This is because some DNS servers |
5238e957 | 736 | * erroneously return NXDOMAIN/SERVFAIL for empty non-terminals (Akamai...) or missing DS |
b3c6b00a LP |
737 | * records (Facebook), and we need to handle that nicely, when asking for parent SOA or similar |
738 | * RRs to make unsigned proofs. */ | |
942eb2e7 LP |
739 | |
740 | case DNS_TRANSACTION_SUCCESS: | |
741 | /* All good. */ | |
742 | break; | |
743 | ||
744 | case DNS_TRANSACTION_DNSSEC_FAILED: | |
745 | /* We handle DNSSEC failures different from other errors, as we care about the DNSSEC | |
746 | * validationr result */ | |
747 | ||
748 | log_debug("Auxiliary DNSSEC RR query failed validation: %s", dnssec_result_to_string(dt->answer_dnssec_result)); | |
749 | t->answer_dnssec_result = dt->answer_dnssec_result; /* Copy error code over */ | |
750 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); | |
751 | return 0; | |
752 | ||
942eb2e7 LP |
753 | default: |
754 | log_debug("Auxiliary DNSSEC RR query failed with %s", dns_transaction_state_to_string(dt->state)); | |
755 | goto fail; | |
756 | } | |
757 | } | |
758 | ||
759 | /* All is ready, we can go and validate */ | |
760 | return 1; | |
761 | ||
762 | fail: | |
763 | t->answer_dnssec_result = DNSSEC_FAILED_AUXILIARY; | |
764 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); | |
765 | return 0; | |
766 | } | |
767 | ||
547973de LP |
768 | static void dns_transaction_process_dnssec(DnsTransaction *t) { |
769 | int r; | |
770 | ||
771 | assert(t); | |
772 | ||
773 | /* Are there ongoing DNSSEC transactions? If so, let's wait for them. */ | |
942eb2e7 | 774 | r = dns_transaction_dnssec_ready(t); |
7cc6ed7b LP |
775 | if (r < 0) |
776 | goto fail; | |
942eb2e7 | 777 | if (r == 0) /* We aren't ready yet (or one of our auxiliary transactions failed, and we shouldn't validate now */ |
547973de LP |
778 | return; |
779 | ||
c02cf2f4 LP |
780 | /* See if we learnt things from the additional DNSSEC transactions, that we didn't know before, and better |
781 | * restart the lookup immediately. */ | |
782 | r = dns_transaction_maybe_restart(t); | |
7cc6ed7b LP |
783 | if (r < 0) |
784 | goto fail; | |
c02cf2f4 LP |
785 | if (r > 0) /* Transaction got restarted... */ |
786 | return; | |
787 | ||
547973de LP |
788 | /* All our auxiliary DNSSEC transactions are complete now. Try |
789 | * to validate our RRset now. */ | |
790 | r = dns_transaction_validate_dnssec(t); | |
fcfaff12 LP |
791 | if (r == -EBADMSG) { |
792 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
793 | return; | |
794 | } | |
7cc6ed7b LP |
795 | if (r < 0) |
796 | goto fail; | |
547973de | 797 | |
b652d4a2 LP |
798 | if (t->answer_dnssec_result == DNSSEC_INCOMPATIBLE_SERVER && |
799 | t->scope->dnssec_mode == DNSSEC_YES) { | |
e82b1132 LP |
800 | |
801 | /* We are not in automatic downgrade mode, and the server is bad. Let's try a different server, maybe | |
802 | * that works. */ | |
803 | ||
804 | if (t->n_picked_servers < dns_scope_get_n_dns_servers(t->scope)) { | |
805 | /* We tried fewer servers on this transaction than we know, let's try another one then */ | |
806 | dns_transaction_retry(t, true); | |
807 | return; | |
808 | } | |
809 | ||
810 | /* OK, let's give up, apparently all servers we tried didn't work. */ | |
b652d4a2 LP |
811 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); |
812 | return; | |
813 | } | |
814 | ||
019036a4 | 815 | if (!IN_SET(t->answer_dnssec_result, |
b652d4a2 LP |
816 | _DNSSEC_RESULT_INVALID, /* No DNSSEC validation enabled */ |
817 | DNSSEC_VALIDATED, /* Answer is signed and validated successfully */ | |
818 | DNSSEC_UNSIGNED, /* Answer is right-fully unsigned */ | |
819 | DNSSEC_INCOMPATIBLE_SERVER)) { /* Server does not do DNSSEC (Yay, we are downgrade attack vulnerable!) */ | |
547973de LP |
820 | dns_transaction_complete(t, DNS_TRANSACTION_DNSSEC_FAILED); |
821 | return; | |
822 | } | |
823 | ||
1e02e182 LP |
824 | if (t->answer_dnssec_result == DNSSEC_INCOMPATIBLE_SERVER) |
825 | dns_server_warn_downgrade(t->server); | |
826 | ||
547973de LP |
827 | dns_transaction_cache_answer(t); |
828 | ||
829 | if (t->answer_rcode == DNS_RCODE_SUCCESS) | |
830 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); | |
831 | else | |
3bbdc31d | 832 | dns_transaction_complete(t, DNS_TRANSACTION_RCODE_FAILURE); |
7cc6ed7b LP |
833 | |
834 | return; | |
835 | ||
836 | fail: | |
837 | t->answer_errno = -r; | |
838 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); | |
547973de LP |
839 | } |
840 | ||
eac7cda2 LP |
841 | static int dns_transaction_has_positive_answer(DnsTransaction *t, DnsAnswerFlags *flags) { |
842 | int r; | |
843 | ||
844 | assert(t); | |
845 | ||
846 | /* Checks whether the answer is positive, i.e. either a direct | |
847 | * answer to the question, or a CNAME/DNAME for it */ | |
848 | ||
849 | r = dns_answer_match_key(t->answer, t->key, flags); | |
850 | if (r != 0) | |
851 | return r; | |
852 | ||
853 | r = dns_answer_find_cname_or_dname(t->answer, t->key, NULL, flags); | |
854 | if (r != 0) | |
855 | return r; | |
856 | ||
857 | return false; | |
858 | } | |
859 | ||
860 | static int dns_transaction_fix_rcode(DnsTransaction *t) { | |
861 | int r; | |
862 | ||
863 | assert(t); | |
864 | ||
865 | /* Fix up the RCODE to SUCCESS if we get at least one matching RR in a response. Note that this contradicts the | |
866 | * DNS RFCs a bit. Specifically, RFC 6604 Section 3 clarifies that the RCODE shall say something about a | |
867 | * CNAME/DNAME chain element coming after the last chain element contained in the message, and not the first | |
868 | * one included. However, it also indicates that not all DNS servers implement this correctly. Moreover, when | |
869 | * using DNSSEC we usually only can prove the first element of a CNAME/DNAME chain anyway, hence let's settle | |
870 | * on always processing the RCODE as referring to the immediate look-up we do, i.e. the first element of a | |
871 | * CNAME/DNAME chain. This way, we uniformly handle CNAME/DNAME chains, regardless if the DNS server | |
872 | * incorrectly implements RCODE, whether DNSSEC is in use, or whether the DNS server only supplied us with an | |
873 | * incomplete CNAME/DNAME chain. | |
874 | * | |
875 | * Or in other words: if we get at least one positive reply in a message we patch NXDOMAIN to become SUCCESS, | |
876 | * and then rely on the CNAME chasing logic to figure out that there's actually a CNAME error with a new | |
877 | * lookup. */ | |
878 | ||
879 | if (t->answer_rcode != DNS_RCODE_NXDOMAIN) | |
880 | return 0; | |
881 | ||
882 | r = dns_transaction_has_positive_answer(t, NULL); | |
883 | if (r <= 0) | |
884 | return r; | |
885 | ||
886 | t->answer_rcode = DNS_RCODE_SUCCESS; | |
887 | return 0; | |
888 | } | |
889 | ||
ec2c5e43 | 890 | void dns_transaction_process_reply(DnsTransaction *t, DnsPacket *p) { |
9df3ba6c | 891 | usec_t ts; |
ec2c5e43 LP |
892 | int r; |
893 | ||
894 | assert(t); | |
895 | assert(p); | |
9df3ba6c TG |
896 | assert(t->scope); |
897 | assert(t->scope->manager); | |
ec2c5e43 | 898 | |
5a7e41a3 LP |
899 | if (t->state != DNS_TRANSACTION_PENDING) |
900 | return; | |
901 | ||
ec2c5e43 LP |
902 | /* Note that this call might invalidate the query. Callers |
903 | * should hence not attempt to access the query or transaction | |
904 | * after calling this function. */ | |
905 | ||
11833205 ZJS |
906 | log_debug("Processing incoming packet on transaction %" PRIu16" (rcode=%s).", |
907 | t->id, dns_rcode_to_string(DNS_PACKET_RCODE(p))); | |
b5efcf29 | 908 | |
106784eb | 909 | switch (t->scope->protocol) { |
b5efcf29 | 910 | |
106784eb | 911 | case DNS_PROTOCOL_LLMNR: |
97ebebbc | 912 | /* For LLMNR we will not accept any packets from other interfaces */ |
ec2c5e43 | 913 | |
97ebebbc | 914 | if (p->ifindex != dns_scope_ifindex(t->scope)) |
ec2c5e43 LP |
915 | return; |
916 | ||
917 | if (p->family != t->scope->family) | |
918 | return; | |
919 | ||
920 | /* Tentative packets are not full responses but still | |
921 | * useful for identifying uniqueness conflicts during | |
922 | * probing. */ | |
8b757a38 | 923 | if (DNS_PACKET_LLMNR_T(p)) { |
ec2c5e43 LP |
924 | dns_transaction_tentative(t, p); |
925 | return; | |
926 | } | |
106784eb DM |
927 | |
928 | break; | |
929 | ||
4e5bf5e1 | 930 | case DNS_PROTOCOL_MDNS: |
4e5bf5e1 | 931 | /* For mDNS we will not accept any packets from other interfaces */ |
97ebebbc LP |
932 | |
933 | if (p->ifindex != dns_scope_ifindex(t->scope)) | |
4e5bf5e1 DM |
934 | return; |
935 | ||
936 | if (p->family != t->scope->family) | |
937 | return; | |
938 | ||
939 | break; | |
940 | ||
106784eb | 941 | case DNS_PROTOCOL_DNS: |
8ad182a1 LP |
942 | /* Note that we do not need to verify the |
943 | * addresses/port numbers of incoming traffic, as we | |
944 | * invoked connect() on our UDP socket in which case | |
945 | * the kernel already does the needed verification for | |
946 | * us. */ | |
106784eb DM |
947 | break; |
948 | ||
949 | default: | |
9c56a6f3 | 950 | assert_not_reached("Invalid DNS protocol."); |
ec2c5e43 LP |
951 | } |
952 | ||
ec2c5e43 LP |
953 | if (t->received != p) { |
954 | dns_packet_unref(t->received); | |
955 | t->received = dns_packet_ref(p); | |
956 | } | |
957 | ||
c3bc53e6 LP |
958 | t->answer_source = DNS_TRANSACTION_NETWORK; |
959 | ||
ec2c5e43 LP |
960 | if (p->ipproto == IPPROTO_TCP) { |
961 | if (DNS_PACKET_TC(p)) { | |
962 | /* Truncated via TCP? Somebody must be fucking with us */ | |
963 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
964 | return; | |
965 | } | |
966 | ||
967 | if (DNS_PACKET_ID(p) != t->id) { | |
968 | /* Not the reply to our query? Somebody must be fucking with us */ | |
969 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
970 | return; | |
971 | } | |
972 | } | |
973 | ||
38a03f06 | 974 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); |
9df3ba6c TG |
975 | |
976 | switch (t->scope->protocol) { | |
8af5b883 | 977 | |
9df3ba6c TG |
978 | case DNS_PROTOCOL_DNS: |
979 | assert(t->server); | |
980 | ||
4e0b8b17 TG |
981 | if (IN_SET(DNS_PACKET_RCODE(p), DNS_RCODE_FORMERR, DNS_RCODE_SERVFAIL, DNS_RCODE_NOTIMP)) { |
982 | ||
8af5b883 | 983 | /* Request failed, immediately try again with reduced features */ |
4e0b8b17 | 984 | |
7d581a65 | 985 | if (t->current_feature_level <= DNS_SERVER_FEATURE_LEVEL_UDP) { |
44db02d0 | 986 | |
7d581a65 | 987 | /* This was already at UDP feature level? If so, it doesn't make sense to downgrade |
44db02d0 LP |
988 | * this transaction anymore, but let's see if it might make sense to send the request |
989 | * to a different DNS server instead. If not let's process the response, and accept the | |
7d581a65 LP |
990 | * rcode. Note that we don't retry on TCP, since that's a suitable way to mitigate |
991 | * packet loss, but is not going to give us better rcodes should we actually have | |
992 | * managed to get them already at UDP level. */ | |
993 | ||
44db02d0 LP |
994 | if (t->n_picked_servers < dns_scope_get_n_dns_servers(t->scope)) { |
995 | /* We tried fewer servers on this transaction than we know, let's try another one then */ | |
996 | dns_transaction_retry(t, true); | |
997 | return; | |
998 | } | |
999 | ||
1000 | /* Give up, accept the rcode */ | |
d001e0a3 LP |
1001 | log_debug("Server returned error: %s", dns_rcode_to_string(DNS_PACKET_RCODE(p))); |
1002 | break; | |
1003 | } | |
1004 | ||
1005 | /* Reduce this feature level by one and try again. */ | |
5d67a7ae IT |
1006 | switch (t->current_feature_level) { |
1007 | case DNS_SERVER_FEATURE_LEVEL_TLS_DO: | |
1008 | t->clamp_feature_level = DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN; | |
1009 | break; | |
1010 | case DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN + 1: | |
1011 | /* Skip plain TLS when TLS is not supported */ | |
1012 | t->clamp_feature_level = DNS_SERVER_FEATURE_LEVEL_TLS_PLAIN - 1; | |
1013 | break; | |
1014 | default: | |
1015 | t->clamp_feature_level = t->current_feature_level - 1; | |
1016 | } | |
d001e0a3 LP |
1017 | |
1018 | log_debug("Server returned error %s, retrying transaction with reduced feature level %s.", | |
1019 | dns_rcode_to_string(DNS_PACKET_RCODE(p)), | |
1020 | dns_server_feature_level_to_string(t->clamp_feature_level)); | |
1021 | ||
1022 | dns_transaction_retry(t, false /* use the same server */); | |
4e0b8b17 | 1023 | return; |
eb08640a LP |
1024 | } |
1025 | ||
1026 | if (DNS_PACKET_RCODE(p) == DNS_RCODE_REFUSED) { | |
1027 | /* This server refused our request? If so, try again, use a different server */ | |
1028 | log_debug("Server returned REFUSED, switching servers, and retrying."); | |
1029 | dns_transaction_retry(t, true /* pick a new server */); | |
1030 | return; | |
1031 | } | |
1032 | ||
1033 | if (DNS_PACKET_TC(p)) | |
274b8748 | 1034 | dns_server_packet_truncated(t->server, t->current_feature_level); |
9df3ba6c TG |
1035 | |
1036 | break; | |
8af5b883 | 1037 | |
9df3ba6c TG |
1038 | case DNS_PROTOCOL_LLMNR: |
1039 | case DNS_PROTOCOL_MDNS: | |
1040 | dns_scope_packet_received(t->scope, ts - t->start_usec); | |
9df3ba6c | 1041 | break; |
8af5b883 | 1042 | |
9df3ba6c | 1043 | default: |
8af5b883 | 1044 | assert_not_reached("Invalid DNS protocol."); |
9df3ba6c TG |
1045 | } |
1046 | ||
ec2c5e43 | 1047 | if (DNS_PACKET_TC(p)) { |
547493c5 DM |
1048 | |
1049 | /* Truncated packets for mDNS are not allowed. Give up immediately. */ | |
1050 | if (t->scope->protocol == DNS_PROTOCOL_MDNS) { | |
1051 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
1052 | return; | |
1053 | } | |
1054 | ||
f757cd85 LP |
1055 | log_debug("Reply truncated, retrying via TCP."); |
1056 | ||
ec2c5e43 | 1057 | /* Response was truncated, let's try again with good old TCP */ |
98767d75 | 1058 | r = dns_transaction_emit_tcp(t); |
ec2c5e43 LP |
1059 | if (r == -ESRCH) { |
1060 | /* No servers found? Damn! */ | |
1061 | dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS); | |
1062 | return; | |
1063 | } | |
91adc4db LP |
1064 | if (r == -EOPNOTSUPP) { |
1065 | /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */ | |
1066 | dns_transaction_complete(t, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED); | |
1067 | return; | |
1068 | } | |
ec2c5e43 | 1069 | if (r < 0) { |
8af5b883 | 1070 | /* On LLMNR, if we cannot connect to the host, |
ec2c5e43 | 1071 | * we immediately give up */ |
7cc6ed7b LP |
1072 | if (t->scope->protocol != DNS_PROTOCOL_DNS) |
1073 | goto fail; | |
ec2c5e43 LP |
1074 | |
1075 | /* On DNS, couldn't send? Try immediately again, with a new server */ | |
d001e0a3 | 1076 | dns_transaction_retry(t, true); |
ec2c5e43 | 1077 | } |
2a6658ef LP |
1078 | |
1079 | return; | |
ec2c5e43 LP |
1080 | } |
1081 | ||
de54e62b | 1082 | /* After the superficial checks, actually parse the message. */ |
ec2c5e43 LP |
1083 | r = dns_packet_extract(p); |
1084 | if (r < 0) { | |
1085 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
1086 | return; | |
1087 | } | |
1088 | ||
ed9717fc | 1089 | if (t->server) { |
d001e0a3 LP |
1090 | /* Report that we successfully received a valid packet with a good rcode after we initially got a bad |
1091 | * rcode and subsequently downgraded the protocol */ | |
1092 | ||
1093 | if (IN_SET(DNS_PACKET_RCODE(p), DNS_RCODE_SUCCESS, DNS_RCODE_NXDOMAIN) && | |
1094 | t->clamp_feature_level != _DNS_SERVER_FEATURE_LEVEL_INVALID) | |
1095 | dns_server_packet_rcode_downgrade(t->server, t->clamp_feature_level); | |
1096 | ||
1097 | /* Report that the OPT RR was missing */ | |
ed9717fc LP |
1098 | if (!p->opt) |
1099 | dns_server_packet_bad_opt(t->server, t->current_feature_level); | |
1100 | ||
d001e0a3 | 1101 | /* Report that we successfully received a packet */ |
dbc4661a | 1102 | dns_server_packet_received(t->server, p->ipproto, t->current_feature_level, p->size); |
ed9717fc | 1103 | } |
de54e62b | 1104 | |
c02cf2f4 LP |
1105 | /* See if we know things we didn't know before that indicate we better restart the lookup immediately. */ |
1106 | r = dns_transaction_maybe_restart(t); | |
7cc6ed7b LP |
1107 | if (r < 0) |
1108 | goto fail; | |
c02cf2f4 LP |
1109 | if (r > 0) /* Transaction got restarted... */ |
1110 | return; | |
1111 | ||
8b419837 | 1112 | if (IN_SET(t->scope->protocol, DNS_PROTOCOL_DNS, DNS_PROTOCOL_LLMNR, DNS_PROTOCOL_MDNS)) { |
b5efcf29 | 1113 | |
8b419837 DR |
1114 | /* When dealing with protocols other than mDNS only consider responses with |
1115 | * equivalent query section to the request. For mDNS this check doesn't make | |
1116 | * sense, because the section 6 of RFC6762 states that "Multicast DNS responses MUST NOT | |
1117 | * contain any questions in the Question Section". */ | |
1118 | if (t->scope->protocol != DNS_PROTOCOL_MDNS) { | |
1119 | r = dns_packet_is_reply_for(p, t->key); | |
1120 | if (r < 0) | |
1121 | goto fail; | |
1122 | if (r == 0) { | |
1123 | dns_transaction_complete(t, DNS_TRANSACTION_INVALID_REPLY); | |
1124 | return; | |
1125 | } | |
547493c5 | 1126 | } |
29815b6c | 1127 | |
547493c5 DM |
1128 | /* Install the answer as answer to the transaction */ |
1129 | dns_answer_unref(t->answer); | |
1130 | t->answer = dns_answer_ref(p->answer); | |
1131 | t->answer_rcode = DNS_PACKET_RCODE(p); | |
919c2ae0 | 1132 | t->answer_dnssec_result = _DNSSEC_RESULT_INVALID; |
105e1512 | 1133 | t->answer_authenticated = false; |
79e24931 | 1134 | |
eac7cda2 LP |
1135 | r = dns_transaction_fix_rcode(t); |
1136 | if (r < 0) | |
1137 | goto fail; | |
1138 | ||
51e399bc LP |
1139 | /* Block GC while starting requests for additional DNSSEC RRs */ |
1140 | t->block_gc++; | |
547973de | 1141 | r = dns_transaction_request_dnssec_keys(t); |
51e399bc LP |
1142 | t->block_gc--; |
1143 | ||
1144 | /* Maybe the transaction is ready for GC'ing now? If so, free it and return. */ | |
1145 | if (!dns_transaction_gc(t)) | |
1146 | return; | |
1147 | ||
1148 | /* Requesting additional keys might have resulted in | |
1149 | * this transaction to fail, since the auxiliary | |
1150 | * request failed for some reason. If so, we are not | |
1151 | * in pending state anymore, and we should exit | |
1152 | * quickly. */ | |
1153 | if (t->state != DNS_TRANSACTION_PENDING) | |
1154 | return; | |
7cc6ed7b LP |
1155 | if (r < 0) |
1156 | goto fail; | |
547973de LP |
1157 | if (r > 0) { |
1158 | /* There are DNSSEC transactions pending now. Update the state accordingly. */ | |
1159 | t->state = DNS_TRANSACTION_VALIDATING; | |
f535705a LP |
1160 | dns_transaction_close_connection(t); |
1161 | dns_transaction_stop_timeout(t); | |
547973de LP |
1162 | return; |
1163 | } | |
547493c5 | 1164 | } |
ec2c5e43 | 1165 | |
547973de | 1166 | dns_transaction_process_dnssec(t); |
7cc6ed7b LP |
1167 | return; |
1168 | ||
1169 | fail: | |
1170 | t->answer_errno = -r; | |
1171 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); | |
ec2c5e43 LP |
1172 | } |
1173 | ||
c19ffd9f TG |
1174 | static int on_dns_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { |
1175 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
1176 | DnsTransaction *t = userdata; | |
1177 | int r; | |
1178 | ||
1179 | assert(t); | |
1180 | assert(t->scope); | |
1181 | ||
1182 | r = manager_recv(t->scope->manager, fd, DNS_PROTOCOL_DNS, &p); | |
7e1851e3 LP |
1183 | if (ERRNO_IS_DISCONNECT(-r)) { |
1184 | usec_t usec; | |
c19ffd9f | 1185 | |
f731fd5b ZJS |
1186 | /* UDP connection failures get reported via ICMP and then are possibly delivered to us on the |
1187 | * next recvmsg(). Treat this like a lost packet. */ | |
7e1851e3 | 1188 | |
92ec902a | 1189 | log_debug_errno(r, "Connection failure for DNS UDP packet: %m"); |
7e1851e3 | 1190 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &usec) >= 0); |
3da3cdd5 | 1191 | dns_server_packet_lost(t->server, IPPROTO_UDP, t->current_feature_level); |
7e1851e3 | 1192 | |
d001e0a3 | 1193 | dns_transaction_retry(t, true); |
7e1851e3 LP |
1194 | return 0; |
1195 | } | |
1196 | if (r < 0) { | |
7cc6ed7b LP |
1197 | dns_transaction_complete(t, DNS_TRANSACTION_ERRNO); |
1198 | t->answer_errno = -r; | |
7e1851e3 LP |
1199 | return 0; |
1200 | } | |
f731fd5b ZJS |
1201 | if (r == 0) |
1202 | /* Spurious wakeup without any data */ | |
1203 | return 0; | |
7e1851e3 LP |
1204 | |
1205 | r = dns_packet_validate_reply(p); | |
1206 | if (r < 0) { | |
1207 | log_debug_errno(r, "Received invalid DNS packet as response, ignoring: %m"); | |
1208 | return 0; | |
1209 | } | |
1210 | if (r == 0) { | |
e09f605e | 1211 | log_debug("Received inappropriate DNS packet as response, ignoring."); |
7e1851e3 LP |
1212 | return 0; |
1213 | } | |
1214 | ||
1215 | if (DNS_PACKET_ID(p) != t->id) { | |
e09f605e | 1216 | log_debug("Received packet with incorrect transaction ID, ignoring."); |
7e1851e3 LP |
1217 | return 0; |
1218 | } | |
c19ffd9f | 1219 | |
7e1851e3 | 1220 | dns_transaction_process_reply(t, p); |
c19ffd9f TG |
1221 | return 0; |
1222 | } | |
1223 | ||
49cce12d | 1224 | static int dns_transaction_emit_udp(DnsTransaction *t) { |
c19ffd9f TG |
1225 | int r; |
1226 | ||
1227 | assert(t); | |
c19ffd9f | 1228 | |
519ef046 | 1229 | if (t->scope->protocol == DNS_PROTOCOL_DNS) { |
c19ffd9f | 1230 | |
519ef046 | 1231 | r = dns_transaction_pick_server(t); |
471d40d9 TG |
1232 | if (r < 0) |
1233 | return r; | |
c19ffd9f | 1234 | |
5d67a7ae | 1235 | if (t->current_feature_level < DNS_SERVER_FEATURE_LEVEL_UDP || DNS_SERVER_FEATURE_LEVEL_IS_TLS(t->current_feature_level)) |
7d581a65 | 1236 | return -EAGAIN; /* Sorry, can't do UDP, try TCP! */ |
519ef046 | 1237 | |
92ec902a | 1238 | if (!dns_server_dnssec_supported(t->server) && dns_type_is_dnssec(t->key->type)) |
91adc4db LP |
1239 | return -EOPNOTSUPP; |
1240 | ||
519ef046 LP |
1241 | if (r > 0 || t->dns_udp_fd < 0) { /* Server changed, or no connection yet. */ |
1242 | int fd; | |
1243 | ||
1244 | dns_transaction_close_connection(t); | |
c19ffd9f | 1245 | |
519ef046 LP |
1246 | fd = dns_scope_socket_udp(t->scope, t->server, 53); |
1247 | if (fd < 0) | |
1248 | return fd; | |
1249 | ||
1250 | r = sd_event_add_io(t->scope->manager->event, &t->dns_udp_event_source, fd, EPOLLIN, on_dns_packet, t); | |
1251 | if (r < 0) { | |
1252 | safe_close(fd); | |
1253 | return r; | |
1254 | } | |
1255 | ||
aa4a9deb | 1256 | (void) sd_event_source_set_description(t->dns_udp_event_source, "dns-transaction-udp"); |
519ef046 LP |
1257 | t->dns_udp_fd = fd; |
1258 | } | |
1259 | ||
274b8748 | 1260 | r = dns_server_adjust_opt(t->server, t->sent, t->current_feature_level); |
519ef046 LP |
1261 | if (r < 0) |
1262 | return r; | |
1263 | } else | |
1264 | dns_transaction_close_connection(t); | |
1265 | ||
1266 | r = dns_scope_emit_udp(t->scope, t->dns_udp_fd, t->sent); | |
471d40d9 TG |
1267 | if (r < 0) |
1268 | return r; | |
c19ffd9f | 1269 | |
519ef046 | 1270 | dns_transaction_reset_answer(t); |
be808ea0 | 1271 | |
471d40d9 | 1272 | return 0; |
c19ffd9f TG |
1273 | } |
1274 | ||
ec2c5e43 LP |
1275 | static int on_transaction_timeout(sd_event_source *s, usec_t usec, void *userdata) { |
1276 | DnsTransaction *t = userdata; | |
ec2c5e43 LP |
1277 | |
1278 | assert(s); | |
1279 | assert(t); | |
1280 | ||
ef7ce6df DM |
1281 | if (!t->initial_jitter_scheduled || t->initial_jitter_elapsed) { |
1282 | /* Timeout reached? Increase the timeout for the server used */ | |
1283 | switch (t->scope->protocol) { | |
49cce12d | 1284 | |
ef7ce6df DM |
1285 | case DNS_PROTOCOL_DNS: |
1286 | assert(t->server); | |
3da3cdd5 | 1287 | dns_server_packet_lost(t->server, t->stream ? IPPROTO_TCP : IPPROTO_UDP, t->current_feature_level); |
ef7ce6df | 1288 | break; |
49cce12d | 1289 | |
ef7ce6df DM |
1290 | case DNS_PROTOCOL_LLMNR: |
1291 | case DNS_PROTOCOL_MDNS: | |
1292 | dns_scope_packet_lost(t->scope, usec - t->start_usec); | |
ef7ce6df | 1293 | break; |
49cce12d | 1294 | |
ef7ce6df DM |
1295 | default: |
1296 | assert_not_reached("Invalid DNS protocol."); | |
1297 | } | |
1298 | ||
1299 | if (t->initial_jitter_scheduled) | |
1300 | t->initial_jitter_elapsed = true; | |
be808ea0 TG |
1301 | } |
1302 | ||
423659ab LP |
1303 | log_debug("Timeout reached on transaction %" PRIu16 ".", t->id); |
1304 | ||
d001e0a3 | 1305 | dns_transaction_retry(t, true); |
ec2c5e43 LP |
1306 | return 0; |
1307 | } | |
1308 | ||
9df3ba6c TG |
1309 | static usec_t transaction_get_resend_timeout(DnsTransaction *t) { |
1310 | assert(t); | |
1311 | assert(t->scope); | |
1312 | ||
1313 | switch (t->scope->protocol) { | |
49cce12d | 1314 | |
9df3ba6c | 1315 | case DNS_PROTOCOL_DNS: |
dc349f5f LP |
1316 | |
1317 | /* When we do TCP, grant a much longer timeout, as in this case there's no need for us to quickly | |
1318 | * resend, as the kernel does that anyway for us, and we really don't want to interrupt it in that | |
1319 | * needlessly. */ | |
1320 | if (t->stream) | |
1321 | return TRANSACTION_TCP_TIMEOUT_USEC; | |
1322 | ||
dbc4661a | 1323 | return DNS_TIMEOUT_USEC; |
49cce12d | 1324 | |
9df3ba6c | 1325 | case DNS_PROTOCOL_MDNS: |
11a27c2e | 1326 | assert(t->n_attempts > 0); |
53fda2bb DR |
1327 | if (t->probing) |
1328 | return MDNS_PROBING_INTERVAL_USEC; | |
1329 | else | |
1330 | return (1 << (t->n_attempts - 1)) * USEC_PER_SEC; | |
49cce12d | 1331 | |
11a27c2e | 1332 | case DNS_PROTOCOL_LLMNR: |
9df3ba6c | 1333 | return t->scope->resend_timeout; |
49cce12d | 1334 | |
9df3ba6c TG |
1335 | default: |
1336 | assert_not_reached("Invalid DNS protocol."); | |
1337 | } | |
1338 | } | |
1339 | ||
c842ff24 | 1340 | static int dns_transaction_prepare(DnsTransaction *t, usec_t ts) { |
ec2c5e43 LP |
1341 | int r; |
1342 | ||
1343 | assert(t); | |
1344 | ||
f535705a | 1345 | dns_transaction_stop_timeout(t); |
ec2c5e43 | 1346 | |
86b112a3 | 1347 | if (!dns_scope_network_good(t->scope)) { |
edbcc1fd LP |
1348 | dns_transaction_complete(t, DNS_TRANSACTION_NETWORK_DOWN); |
1349 | return 0; | |
1350 | } | |
1351 | ||
ec2c5e43 | 1352 | if (t->n_attempts >= TRANSACTION_ATTEMPTS_MAX(t->scope->protocol)) { |
e53b8cc5 ZJS |
1353 | DnsTransactionState result; |
1354 | ||
1355 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR) | |
1356 | /* If we didn't find anything on LLMNR, it's not an error, but a failure to resolve | |
1357 | * the name. */ | |
1358 | result = DNS_TRANSACTION_NOT_FOUND; | |
1359 | else | |
1360 | result = DNS_TRANSACTION_ATTEMPTS_MAX_REACHED; | |
1361 | ||
1362 | dns_transaction_complete(t, result); | |
ec2c5e43 LP |
1363 | return 0; |
1364 | } | |
1365 | ||
cbe4216d | 1366 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR && t->tried_stream) { |
ec2c5e43 LP |
1367 | /* If we already tried via a stream, then we don't |
1368 | * retry on LLMNR. See RFC 4795, Section 2.7. */ | |
1369 | dns_transaction_complete(t, DNS_TRANSACTION_ATTEMPTS_MAX_REACHED); | |
1370 | return 0; | |
1371 | } | |
1372 | ||
1373 | t->n_attempts++; | |
9df3ba6c | 1374 | t->start_usec = ts; |
c61d2b44 LP |
1375 | |
1376 | dns_transaction_reset_answer(t); | |
c5b4f861 | 1377 | dns_transaction_flush_dnssec_transactions(t); |
ec2c5e43 | 1378 | |
0d2cd476 LP |
1379 | /* Check the trust anchor. Do so only on classic DNS, since DNSSEC does not apply otherwise. */ |
1380 | if (t->scope->protocol == DNS_PROTOCOL_DNS) { | |
8e54f5d9 | 1381 | r = dns_trust_anchor_lookup_positive(&t->scope->manager->trust_anchor, t->key, &t->answer); |
0d2cd476 LP |
1382 | if (r < 0) |
1383 | return r; | |
1384 | if (r > 0) { | |
1385 | t->answer_rcode = DNS_RCODE_SUCCESS; | |
1386 | t->answer_source = DNS_TRANSACTION_TRUST_ANCHOR; | |
931851e8 | 1387 | t->answer_authenticated = true; |
0d2cd476 LP |
1388 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); |
1389 | return 0; | |
1390 | } | |
b2b796b8 | 1391 | |
1c02e7ba | 1392 | if (dns_name_is_root(dns_resource_key_name(t->key)) && |
b2b796b8 LP |
1393 | t->key->type == DNS_TYPE_DS) { |
1394 | ||
1395 | /* Hmm, this is a request for the root DS? A | |
1396 | * DS RR doesn't exist in the root zone, and | |
1397 | * if our trust anchor didn't know it either, | |
1398 | * this means we cannot do any DNSSEC logic | |
1399 | * anymore. */ | |
1400 | ||
1ed8c0fb | 1401 | if (t->scope->dnssec_mode == DNSSEC_ALLOW_DOWNGRADE) { |
b2b796b8 LP |
1402 | /* We are in downgrade mode. In this |
1403 | * case, synthesize an unsigned empty | |
1404 | * response, so that the any lookup | |
1405 | * depending on this one can continue | |
1406 | * assuming there was no DS, and hence | |
1407 | * the root zone was unsigned. */ | |
1408 | ||
1409 | t->answer_rcode = DNS_RCODE_SUCCESS; | |
1410 | t->answer_source = DNS_TRANSACTION_TRUST_ANCHOR; | |
1411 | t->answer_authenticated = false; | |
1412 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); | |
1413 | } else | |
1414 | /* If we are not in downgrade mode, | |
1415 | * then fail the lookup, because we | |
1416 | * cannot reasonably answer it. There | |
1417 | * might be DS RRs, but we don't know | |
1418 | * them, and the DNS server won't tell | |
1419 | * them to us (and even if it would, | |
202b76ae | 1420 | * we couldn't validate and trust them. */ |
b2b796b8 LP |
1421 | dns_transaction_complete(t, DNS_TRANSACTION_NO_TRUST_ANCHOR); |
1422 | ||
1423 | return 0; | |
1424 | } | |
0d2cd476 LP |
1425 | } |
1426 | ||
1427 | /* Check the zone, but only if this transaction is not used | |
d746bb3e | 1428 | * for probing or verifying a zone item. */ |
547973de | 1429 | if (set_isempty(t->notify_zone_items)) { |
d746bb3e | 1430 | |
97ebebbc | 1431 | r = dns_zone_lookup(&t->scope->zone, t->key, dns_scope_ifindex(t->scope), &t->answer, NULL, NULL); |
d746bb3e LP |
1432 | if (r < 0) |
1433 | return r; | |
1434 | if (r > 0) { | |
ae6a4bbf | 1435 | t->answer_rcode = DNS_RCODE_SUCCESS; |
c3bc53e6 | 1436 | t->answer_source = DNS_TRANSACTION_ZONE; |
931851e8 | 1437 | t->answer_authenticated = true; |
d746bb3e LP |
1438 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); |
1439 | return 0; | |
1440 | } | |
1441 | } | |
1442 | ||
4d926a69 LP |
1443 | /* Check the cache, but only if this transaction is not used |
1444 | * for probing or verifying a zone item. */ | |
547973de | 1445 | if (set_isempty(t->notify_zone_items)) { |
2c27fbca | 1446 | |
4d926a69 LP |
1447 | /* Before trying the cache, let's make sure we figured out a |
1448 | * server to use. Should this cause a change of server this | |
1449 | * might flush the cache. */ | |
5cdb8930 | 1450 | (void) dns_scope_get_dns_server(t->scope); |
2c27fbca | 1451 | |
4d926a69 LP |
1452 | /* Let's then prune all outdated entries */ |
1453 | dns_cache_prune(&t->scope->cache); | |
1454 | ||
17c8de63 | 1455 | r = dns_cache_lookup(&t->scope->cache, t->key, t->clamp_ttl, &t->answer_rcode, &t->answer, &t->answer_authenticated); |
4d926a69 LP |
1456 | if (r < 0) |
1457 | return r; | |
1458 | if (r > 0) { | |
c3bc53e6 | 1459 | t->answer_source = DNS_TRANSACTION_CACHE; |
ae6a4bbf | 1460 | if (t->answer_rcode == DNS_RCODE_SUCCESS) |
4d926a69 LP |
1461 | dns_transaction_complete(t, DNS_TRANSACTION_SUCCESS); |
1462 | else | |
3bbdc31d | 1463 | dns_transaction_complete(t, DNS_TRANSACTION_RCODE_FAILURE); |
4d926a69 LP |
1464 | return 0; |
1465 | } | |
ec2c5e43 LP |
1466 | } |
1467 | ||
1effe965 DM |
1468 | return 1; |
1469 | } | |
1470 | ||
0afa57e2 DM |
1471 | static int dns_transaction_make_packet_mdns(DnsTransaction *t) { |
1472 | ||
1473 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
7778dfff | 1474 | bool add_known_answers = false; |
0afa57e2 | 1475 | DnsTransaction *other; |
0d5ee47d DR |
1476 | Iterator i; |
1477 | DnsResourceKey *tkey; | |
1478 | _cleanup_set_free_ Set *keys = NULL; | |
0afa57e2 | 1479 | unsigned qdcount; |
0d5ee47d | 1480 | unsigned nscount = 0; |
0afa57e2 DM |
1481 | usec_t ts; |
1482 | int r; | |
1483 | ||
1484 | assert(t); | |
1485 | assert(t->scope->protocol == DNS_PROTOCOL_MDNS); | |
1486 | ||
e5abebab | 1487 | /* Discard any previously prepared packet, so we can start over and coalesce again */ |
0afa57e2 DM |
1488 | t->sent = dns_packet_unref(t->sent); |
1489 | ||
1490 | r = dns_packet_new_query(&p, t->scope->protocol, 0, false); | |
1491 | if (r < 0) | |
1492 | return r; | |
1493 | ||
58ab31d5 | 1494 | r = dns_packet_append_key(p, t->key, 0, NULL); |
0afa57e2 DM |
1495 | if (r < 0) |
1496 | return r; | |
1497 | ||
1498 | qdcount = 1; | |
1499 | ||
7778dfff DM |
1500 | if (dns_key_is_shared(t->key)) |
1501 | add_known_answers = true; | |
1502 | ||
0d5ee47d DR |
1503 | if (t->key->type == DNS_TYPE_ANY) { |
1504 | r = set_ensure_allocated(&keys, &dns_resource_key_hash_ops); | |
1505 | if (r < 0) | |
1506 | return r; | |
1507 | ||
1508 | r = set_put(keys, t->key); | |
1509 | if (r < 0) | |
1510 | return r; | |
1511 | } | |
1512 | ||
0afa57e2 DM |
1513 | /* |
1514 | * For mDNS, we want to coalesce as many open queries in pending transactions into one single | |
1515 | * query packet on the wire as possible. To achieve that, we iterate through all pending transactions | |
5238e957 | 1516 | * in our current scope, and see whether their timing constraints allow them to be sent. |
0afa57e2 DM |
1517 | */ |
1518 | ||
1519 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); | |
1520 | ||
1521 | LIST_FOREACH(transactions_by_scope, other, t->scope->transactions) { | |
1522 | ||
1523 | /* Skip ourselves */ | |
1524 | if (other == t) | |
1525 | continue; | |
1526 | ||
1527 | if (other->state != DNS_TRANSACTION_PENDING) | |
1528 | continue; | |
1529 | ||
1530 | if (other->next_attempt_after > ts) | |
1531 | continue; | |
1532 | ||
1533 | if (qdcount >= UINT16_MAX) | |
1534 | break; | |
1535 | ||
58ab31d5 | 1536 | r = dns_packet_append_key(p, other->key, 0, NULL); |
0afa57e2 DM |
1537 | |
1538 | /* | |
1539 | * If we can't stuff more questions into the packet, just give up. | |
1540 | * One of the 'other' transactions will fire later and take care of the rest. | |
1541 | */ | |
1542 | if (r == -EMSGSIZE) | |
1543 | break; | |
1544 | ||
1545 | if (r < 0) | |
1546 | return r; | |
1547 | ||
c842ff24 | 1548 | r = dns_transaction_prepare(other, ts); |
0afa57e2 DM |
1549 | if (r <= 0) |
1550 | continue; | |
1551 | ||
1552 | ts += transaction_get_resend_timeout(other); | |
1553 | ||
1554 | r = sd_event_add_time( | |
1555 | other->scope->manager->event, | |
1556 | &other->timeout_event_source, | |
1557 | clock_boottime_or_monotonic(), | |
1558 | ts, 0, | |
1559 | on_transaction_timeout, other); | |
1560 | if (r < 0) | |
1561 | return r; | |
1562 | ||
ff537038 | 1563 | (void) sd_event_source_set_description(other->timeout_event_source, "dns-transaction-timeout"); |
aa4a9deb | 1564 | |
0afa57e2 DM |
1565 | other->state = DNS_TRANSACTION_PENDING; |
1566 | other->next_attempt_after = ts; | |
1567 | ||
313cefa1 | 1568 | qdcount++; |
7778dfff DM |
1569 | |
1570 | if (dns_key_is_shared(other->key)) | |
1571 | add_known_answers = true; | |
0d5ee47d DR |
1572 | |
1573 | if (other->key->type == DNS_TYPE_ANY) { | |
1574 | r = set_ensure_allocated(&keys, &dns_resource_key_hash_ops); | |
1575 | if (r < 0) | |
1576 | return r; | |
1577 | ||
1578 | r = set_put(keys, other->key); | |
1579 | if (r < 0) | |
1580 | return r; | |
1581 | } | |
0afa57e2 DM |
1582 | } |
1583 | ||
1584 | DNS_PACKET_HEADER(p)->qdcount = htobe16(qdcount); | |
0afa57e2 | 1585 | |
7778dfff DM |
1586 | /* Append known answer section if we're asking for any shared record */ |
1587 | if (add_known_answers) { | |
1588 | r = dns_cache_export_shared_to_packet(&t->scope->cache, p); | |
1589 | if (r < 0) | |
1590 | return r; | |
1591 | } | |
1592 | ||
0d5ee47d DR |
1593 | SET_FOREACH(tkey, keys, i) { |
1594 | _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; | |
1595 | bool tentative; | |
1596 | ||
1597 | r = dns_zone_lookup(&t->scope->zone, tkey, t->scope->link->ifindex, &answer, NULL, &tentative); | |
1598 | if (r < 0) | |
1599 | return r; | |
1600 | ||
1601 | r = dns_packet_append_answer(p, answer); | |
1602 | if (r < 0) | |
1603 | return r; | |
1604 | ||
1605 | nscount += dns_answer_size(answer); | |
1606 | } | |
1607 | DNS_PACKET_HEADER(p)->nscount = htobe16(nscount); | |
1608 | ||
1cc6c93a | 1609 | t->sent = TAKE_PTR(p); |
0afa57e2 DM |
1610 | |
1611 | return 0; | |
1612 | } | |
1613 | ||
1614 | static int dns_transaction_make_packet(DnsTransaction *t) { | |
1615 | _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; | |
1616 | int r; | |
1617 | ||
1618 | assert(t); | |
1619 | ||
1620 | if (t->scope->protocol == DNS_PROTOCOL_MDNS) | |
1621 | return dns_transaction_make_packet_mdns(t); | |
1622 | ||
1623 | if (t->sent) | |
1624 | return 0; | |
1625 | ||
b652d4a2 | 1626 | r = dns_packet_new_query(&p, t->scope->protocol, 0, t->scope->dnssec_mode != DNSSEC_NO); |
0afa57e2 DM |
1627 | if (r < 0) |
1628 | return r; | |
1629 | ||
58ab31d5 | 1630 | r = dns_packet_append_key(p, t->key, 0, NULL); |
0afa57e2 DM |
1631 | if (r < 0) |
1632 | return r; | |
1633 | ||
1634 | DNS_PACKET_HEADER(p)->qdcount = htobe16(1); | |
1635 | DNS_PACKET_HEADER(p)->id = t->id; | |
1636 | ||
1cc6c93a | 1637 | t->sent = TAKE_PTR(p); |
0afa57e2 DM |
1638 | |
1639 | return 0; | |
1640 | } | |
1641 | ||
1effe965 DM |
1642 | int dns_transaction_go(DnsTransaction *t) { |
1643 | usec_t ts; | |
1644 | int r; | |
202b76ae | 1645 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
1effe965 DM |
1646 | |
1647 | assert(t); | |
1648 | ||
5278bbfe LP |
1649 | /* Returns > 0 if the transaction is now pending, returns 0 if could be processed immediately and has finished |
1650 | * now. */ | |
1651 | ||
1effe965 | 1652 | assert_se(sd_event_now(t->scope->manager->event, clock_boottime_or_monotonic(), &ts) >= 0); |
547973de | 1653 | |
c842ff24 | 1654 | r = dns_transaction_prepare(t, ts); |
1effe965 DM |
1655 | if (r <= 0) |
1656 | return r; | |
1657 | ||
202b76ae | 1658 | log_debug("Transaction %" PRIu16 " for <%s> scope %s on %s/%s.", |
a5784c49 | 1659 | t->id, |
202b76ae | 1660 | dns_resource_key_to_string(t->key, key_str, sizeof key_str), |
a5784c49 | 1661 | dns_protocol_to_string(t->scope->protocol), |
6ff79f76 | 1662 | t->scope->link ? t->scope->link->ifname : "*", |
202b76ae | 1663 | af_to_name_short(t->scope->family)); |
1effe965 | 1664 | |
ef7ce6df | 1665 | if (!t->initial_jitter_scheduled && |
3742095b | 1666 | IN_SET(t->scope->protocol, DNS_PROTOCOL_LLMNR, DNS_PROTOCOL_MDNS)) { |
ea12bcc7 | 1667 | usec_t jitter, accuracy; |
6e068472 LP |
1668 | |
1669 | /* RFC 4795 Section 2.7 suggests all queries should be | |
1670 | * delayed by a random time from 0 to JITTER_INTERVAL. */ | |
1671 | ||
ef7ce6df | 1672 | t->initial_jitter_scheduled = true; |
6e068472 LP |
1673 | |
1674 | random_bytes(&jitter, sizeof(jitter)); | |
ea12bcc7 DM |
1675 | |
1676 | switch (t->scope->protocol) { | |
519ef046 | 1677 | |
ea12bcc7 DM |
1678 | case DNS_PROTOCOL_LLMNR: |
1679 | jitter %= LLMNR_JITTER_INTERVAL_USEC; | |
1680 | accuracy = LLMNR_JITTER_INTERVAL_USEC; | |
1681 | break; | |
519ef046 | 1682 | |
ea12bcc7 DM |
1683 | case DNS_PROTOCOL_MDNS: |
1684 | jitter %= MDNS_JITTER_RANGE_USEC; | |
1685 | jitter += MDNS_JITTER_MIN_USEC; | |
1686 | accuracy = MDNS_JITTER_RANGE_USEC; | |
1687 | break; | |
1688 | default: | |
1689 | assert_not_reached("bad protocol"); | |
1690 | } | |
6e068472 LP |
1691 | |
1692 | r = sd_event_add_time( | |
1693 | t->scope->manager->event, | |
1694 | &t->timeout_event_source, | |
1695 | clock_boottime_or_monotonic(), | |
ea12bcc7 | 1696 | ts + jitter, accuracy, |
6e068472 LP |
1697 | on_transaction_timeout, t); |
1698 | if (r < 0) | |
1699 | return r; | |
1700 | ||
aa4a9deb LP |
1701 | (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout"); |
1702 | ||
6e068472 | 1703 | t->n_attempts = 0; |
a9da14e1 | 1704 | t->next_attempt_after = ts; |
6e068472 LP |
1705 | t->state = DNS_TRANSACTION_PENDING; |
1706 | ||
ea12bcc7 | 1707 | log_debug("Delaying %s transaction for " USEC_FMT "us.", dns_protocol_to_string(t->scope->protocol), jitter); |
6e068472 LP |
1708 | return 0; |
1709 | } | |
1710 | ||
ec2c5e43 LP |
1711 | /* Otherwise, we need to ask the network */ |
1712 | r = dns_transaction_make_packet(t); | |
ec2c5e43 LP |
1713 | if (r < 0) |
1714 | return r; | |
1715 | ||
1716 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR && | |
1c02e7ba ZJS |
1717 | (dns_name_endswith(dns_resource_key_name(t->key), "in-addr.arpa") > 0 || |
1718 | dns_name_endswith(dns_resource_key_name(t->key), "ip6.arpa") > 0)) { | |
ec2c5e43 LP |
1719 | |
1720 | /* RFC 4795, Section 2.4. says reverse lookups shall | |
1721 | * always be made via TCP on LLMNR */ | |
98767d75 | 1722 | r = dns_transaction_emit_tcp(t); |
ec2c5e43 | 1723 | } else { |
be808ea0 TG |
1724 | /* Try via UDP, and if that fails due to large size or lack of |
1725 | * support try via TCP */ | |
49cce12d | 1726 | r = dns_transaction_emit_udp(t); |
29ab0552 LP |
1727 | if (r == -EMSGSIZE) |
1728 | log_debug("Sending query via TCP since it is too large."); | |
dc349f5f | 1729 | else if (r == -EAGAIN) |
5d67a7ae | 1730 | log_debug("Sending query via TCP since UDP isn't supported."); |
4c701096 | 1731 | if (IN_SET(r, -EMSGSIZE, -EAGAIN)) |
98767d75 | 1732 | r = dns_transaction_emit_tcp(t); |
ec2c5e43 | 1733 | } |
be808ea0 | 1734 | |
ec2c5e43 LP |
1735 | if (r == -ESRCH) { |
1736 | /* No servers to send this to? */ | |
1737 | dns_transaction_complete(t, DNS_TRANSACTION_NO_SERVERS); | |
1738 | return 0; | |
91adc4db LP |
1739 | } |
1740 | if (r == -EOPNOTSUPP) { | |
1741 | /* Tried to ask for DNSSEC RRs, on a server that doesn't do DNSSEC */ | |
1742 | dns_transaction_complete(t, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED); | |
1743 | return 0; | |
1744 | } | |
0791110f | 1745 | if (t->scope->protocol == DNS_PROTOCOL_LLMNR && ERRNO_IS_DISCONNECT(-r)) { |
e94968ba | 1746 | /* On LLMNR, if we cannot connect to a host via TCP when doing reverse lookups. This means we cannot |
0791110f LP |
1747 | * answer this request with this protocol. */ |
1748 | dns_transaction_complete(t, DNS_TRANSACTION_NOT_FOUND); | |
1749 | return 0; | |
1750 | } | |
91adc4db | 1751 | if (r < 0) { |
7cc6ed7b LP |
1752 | if (t->scope->protocol != DNS_PROTOCOL_DNS) |
1753 | return r; | |
13b551ac | 1754 | |
ec2c5e43 | 1755 | /* Couldn't send? Try immediately again, with a new server */ |
519ef046 | 1756 | dns_scope_next_dns_server(t->scope); |
ec2c5e43 LP |
1757 | |
1758 | return dns_transaction_go(t); | |
1759 | } | |
1760 | ||
a9da14e1 DM |
1761 | ts += transaction_get_resend_timeout(t); |
1762 | ||
9a015429 LP |
1763 | r = sd_event_add_time( |
1764 | t->scope->manager->event, | |
1765 | &t->timeout_event_source, | |
1766 | clock_boottime_or_monotonic(), | |
a9da14e1 | 1767 | ts, 0, |
9a015429 | 1768 | on_transaction_timeout, t); |
ec2c5e43 LP |
1769 | if (r < 0) |
1770 | return r; | |
1771 | ||
aa4a9deb LP |
1772 | (void) sd_event_source_set_description(t->timeout_event_source, "dns-transaction-timeout"); |
1773 | ||
ec2c5e43 | 1774 | t->state = DNS_TRANSACTION_PENDING; |
a9da14e1 DM |
1775 | t->next_attempt_after = ts; |
1776 | ||
ec2c5e43 LP |
1777 | return 1; |
1778 | } | |
1779 | ||
f2992dc1 LP |
1780 | static int dns_transaction_find_cyclic(DnsTransaction *t, DnsTransaction *aux) { |
1781 | DnsTransaction *n; | |
1782 | Iterator i; | |
1783 | int r; | |
1784 | ||
1785 | assert(t); | |
1786 | assert(aux); | |
1787 | ||
1788 | /* Try to find cyclic dependencies between transaction objects */ | |
1789 | ||
1790 | if (t == aux) | |
1791 | return 1; | |
1792 | ||
3eb6aa00 | 1793 | SET_FOREACH(n, aux->dnssec_transactions, i) { |
f2992dc1 LP |
1794 | r = dns_transaction_find_cyclic(t, n); |
1795 | if (r != 0) | |
1796 | return r; | |
1797 | } | |
1798 | ||
3eb6aa00 | 1799 | return 0; |
f2992dc1 LP |
1800 | } |
1801 | ||
547973de | 1802 | static int dns_transaction_add_dnssec_transaction(DnsTransaction *t, DnsResourceKey *key, DnsTransaction **ret) { |
29bd6012 | 1803 | _cleanup_(dns_transaction_gcp) DnsTransaction *aux = NULL; |
547973de LP |
1804 | int r; |
1805 | ||
1806 | assert(t); | |
1807 | assert(ret); | |
1808 | assert(key); | |
1809 | ||
1810 | aux = dns_scope_find_transaction(t->scope, key, true); | |
1811 | if (!aux) { | |
1812 | r = dns_transaction_new(&aux, t->scope, key); | |
1813 | if (r < 0) | |
1814 | return r; | |
1815 | } else { | |
1816 | if (set_contains(t->dnssec_transactions, aux)) { | |
1817 | *ret = aux; | |
1818 | return 0; | |
1819 | } | |
f2992dc1 LP |
1820 | |
1821 | r = dns_transaction_find_cyclic(t, aux); | |
1822 | if (r < 0) | |
1823 | return r; | |
1824 | if (r > 0) { | |
202b76ae ZJS |
1825 | char s[DNS_RESOURCE_KEY_STRING_MAX], saux[DNS_RESOURCE_KEY_STRING_MAX]; |
1826 | ||
baaa35ad ZJS |
1827 | return log_debug_errno(SYNTHETIC_ERRNO(ELOOP), |
1828 | "Potential cyclic dependency, refusing to add transaction %" PRIu16 " (%s) as dependency for %" PRIu16 " (%s).", | |
1829 | aux->id, | |
1830 | dns_resource_key_to_string(t->key, s, sizeof s), | |
1831 | t->id, | |
1832 | dns_resource_key_to_string(aux->key, saux, sizeof saux)); | |
f2992dc1 | 1833 | } |
547973de LP |
1834 | } |
1835 | ||
1836 | r = set_ensure_allocated(&t->dnssec_transactions, NULL); | |
1837 | if (r < 0) | |
29bd6012 | 1838 | return r;; |
547973de LP |
1839 | |
1840 | r = set_ensure_allocated(&aux->notify_transactions, NULL); | |
1841 | if (r < 0) | |
29bd6012 | 1842 | return r; |
35aa04e9 LP |
1843 | |
1844 | r = set_ensure_allocated(&aux->notify_transactions_done, NULL); | |
1845 | if (r < 0) | |
29bd6012 | 1846 | return r; |
547973de LP |
1847 | |
1848 | r = set_put(t->dnssec_transactions, aux); | |
1849 | if (r < 0) | |
29bd6012 | 1850 | return r; |
547973de LP |
1851 | |
1852 | r = set_put(aux->notify_transactions, t); | |
1853 | if (r < 0) { | |
1854 | (void) set_remove(t->dnssec_transactions, aux); | |
29bd6012 | 1855 | return r; |
547973de LP |
1856 | } |
1857 | ||
29bd6012 | 1858 | *ret = TAKE_PTR(aux); |
547973de | 1859 | return 1; |
547973de LP |
1860 | } |
1861 | ||
1862 | static int dns_transaction_request_dnssec_rr(DnsTransaction *t, DnsResourceKey *key) { | |
1863 | _cleanup_(dns_answer_unrefp) DnsAnswer *a = NULL; | |
1864 | DnsTransaction *aux; | |
1865 | int r; | |
1866 | ||
1867 | assert(t); | |
1868 | assert(key); | |
1869 | ||
1870 | /* Try to get the data from the trust anchor */ | |
8e54f5d9 | 1871 | r = dns_trust_anchor_lookup_positive(&t->scope->manager->trust_anchor, key, &a); |
547973de LP |
1872 | if (r < 0) |
1873 | return r; | |
1874 | if (r > 0) { | |
1875 | r = dns_answer_extend(&t->validated_keys, a); | |
1876 | if (r < 0) | |
1877 | return r; | |
1878 | ||
1879 | return 0; | |
1880 | } | |
1881 | ||
1882 | /* This didn't work, ask for it via the network/cache then. */ | |
1883 | r = dns_transaction_add_dnssec_transaction(t, key, &aux); | |
f2992dc1 LP |
1884 | if (r == -ELOOP) /* This would result in a cyclic dependency */ |
1885 | return 0; | |
547973de LP |
1886 | if (r < 0) |
1887 | return r; | |
1888 | ||
1889 | if (aux->state == DNS_TRANSACTION_NULL) { | |
1890 | r = dns_transaction_go(aux); | |
1891 | if (r < 0) | |
1892 | return r; | |
1893 | } | |
1894 | ||
f2992dc1 | 1895 | return 1; |
547973de LP |
1896 | } |
1897 | ||
8a516214 LP |
1898 | static int dns_transaction_negative_trust_anchor_lookup(DnsTransaction *t, const char *name) { |
1899 | int r; | |
1900 | ||
1901 | assert(t); | |
1902 | ||
c629ff58 | 1903 | /* Check whether the specified name is in the NTA |
8a516214 LP |
1904 | * database, either in the global one, or the link-local |
1905 | * one. */ | |
1906 | ||
1907 | r = dns_trust_anchor_lookup_negative(&t->scope->manager->trust_anchor, name); | |
1908 | if (r != 0) | |
1909 | return r; | |
1910 | ||
1911 | if (!t->scope->link) | |
1912 | return 0; | |
1913 | ||
1914 | return set_contains(t->scope->link->dnssec_negative_trust_anchors, name); | |
1915 | } | |
1916 | ||
105e1512 LP |
1917 | static int dns_transaction_has_unsigned_negative_answer(DnsTransaction *t) { |
1918 | int r; | |
1919 | ||
1920 | assert(t); | |
1921 | ||
1922 | /* Checks whether the answer is negative, and lacks NSEC/NSEC3 | |
1923 | * RRs to prove it */ | |
1924 | ||
1925 | r = dns_transaction_has_positive_answer(t, NULL); | |
1926 | if (r < 0) | |
1927 | return r; | |
1928 | if (r > 0) | |
1929 | return false; | |
1930 | ||
8e54f5d9 LP |
1931 | /* Is this key explicitly listed as a negative trust anchor? |
1932 | * If so, it's nothing we need to care about */ | |
1c02e7ba | 1933 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(t->key)); |
8e54f5d9 LP |
1934 | if (r < 0) |
1935 | return r; | |
1936 | if (r > 0) | |
1937 | return false; | |
1938 | ||
105e1512 LP |
1939 | /* The answer does not contain any RRs that match to the |
1940 | * question. If so, let's see if there are any NSEC/NSEC3 RRs | |
1941 | * included. If not, the answer is unsigned. */ | |
1942 | ||
1943 | r = dns_answer_contains_nsec_or_nsec3(t->answer); | |
1944 | if (r < 0) | |
1945 | return r; | |
1946 | if (r > 0) | |
1947 | return false; | |
1948 | ||
1949 | return true; | |
1950 | } | |
1951 | ||
1952 | static int dns_transaction_is_primary_response(DnsTransaction *t, DnsResourceRecord *rr) { | |
1953 | int r; | |
1954 | ||
1955 | assert(t); | |
1956 | assert(rr); | |
1957 | ||
1958 | /* Check if the specified RR is the "primary" response, | |
1959 | * i.e. either matches the question precisely or is a | |
4cb94977 | 1960 | * CNAME/DNAME for it. */ |
105e1512 LP |
1961 | |
1962 | r = dns_resource_key_match_rr(t->key, rr, NULL); | |
1963 | if (r != 0) | |
1964 | return r; | |
1965 | ||
4cb94977 | 1966 | return dns_resource_key_match_cname_or_dname(t->key, rr->key, NULL); |
105e1512 LP |
1967 | } |
1968 | ||
92ec902a LP |
1969 | static bool dns_transaction_dnssec_supported(DnsTransaction *t) { |
1970 | assert(t); | |
1971 | ||
1972 | /* Checks whether our transaction's DNS server is assumed to be compatible with DNSSEC. Returns false as soon | |
1973 | * as we changed our mind about a server, and now believe it is incompatible with DNSSEC. */ | |
1974 | ||
1975 | if (t->scope->protocol != DNS_PROTOCOL_DNS) | |
1976 | return false; | |
1977 | ||
1978 | /* If we have picked no server, then we are working from the cache or some other source, and DNSSEC might well | |
1979 | * be supported, hence return true. */ | |
1980 | if (!t->server) | |
1981 | return true; | |
1982 | ||
d001e0a3 LP |
1983 | /* Note that we do not check the feature level actually used for the transaction but instead the feature level |
1984 | * the server is known to support currently, as the transaction feature level might be lower than what the | |
1985 | * server actually supports, since we might have downgraded this transaction's feature level because we got a | |
1986 | * SERVFAIL earlier and wanted to check whether downgrading fixes it. */ | |
92ec902a LP |
1987 | |
1988 | return dns_server_dnssec_supported(t->server); | |
1989 | } | |
1990 | ||
1991 | static bool dns_transaction_dnssec_supported_full(DnsTransaction *t) { | |
1992 | DnsTransaction *dt; | |
1993 | Iterator i; | |
1994 | ||
1995 | assert(t); | |
1996 | ||
1997 | /* Checks whether our transaction our any of the auxiliary transactions couldn't do DNSSEC. */ | |
1998 | ||
1999 | if (!dns_transaction_dnssec_supported(t)) | |
2000 | return false; | |
2001 | ||
2002 | SET_FOREACH(dt, t->dnssec_transactions, i) | |
2003 | if (!dns_transaction_dnssec_supported(dt)) | |
2004 | return false; | |
2005 | ||
2006 | return true; | |
2007 | } | |
2008 | ||
547973de LP |
2009 | int dns_transaction_request_dnssec_keys(DnsTransaction *t) { |
2010 | DnsResourceRecord *rr; | |
105e1512 | 2011 | |
547973de LP |
2012 | int r; |
2013 | ||
2014 | assert(t); | |
2015 | ||
105e1512 LP |
2016 | /* |
2017 | * Retrieve all auxiliary RRs for the answer we got, so that | |
2018 | * we can verify signatures or prove that RRs are rightfully | |
2019 | * unsigned. Specifically: | |
2020 | * | |
2021 | * - For RRSIG we get the matching DNSKEY | |
2022 | * - For DNSKEY we get the matching DS | |
2023 | * - For unsigned SOA/NS we get the matching DS | |
b63fca62 | 2024 | * - For unsigned CNAME/DNAME/DS we get the parent SOA RR |
105e1512 | 2025 | * - For other unsigned RRs we get the matching SOA RR |
4bbc06cc LP |
2026 | * - For SOA/NS queries with no matching response RR, and no NSEC/NSEC3, the DS RR |
2027 | * - For DS queries with no matching response RRs, and no NSEC/NSEC3, the parent's SOA RR | |
105e1512 LP |
2028 | * - For other queries with no matching response RRs, and no NSEC/NSEC3, the SOA RR |
2029 | */ | |
2030 | ||
b652d4a2 | 2031 | if (t->scope->dnssec_mode == DNSSEC_NO) |
547973de | 2032 | return 0; |
92ec902a LP |
2033 | if (t->answer_source != DNS_TRANSACTION_NETWORK) |
2034 | return 0; /* We only need to validate stuff from the network */ | |
2035 | if (!dns_transaction_dnssec_supported(t)) | |
5238e957 | 2036 | return 0; /* If we can't do DNSSEC anyway there's no point in getting the auxiliary RRs */ |
b652d4a2 | 2037 | |
547973de LP |
2038 | DNS_ANSWER_FOREACH(rr, t->answer) { |
2039 | ||
105e1512 LP |
2040 | if (dns_type_is_pseudo(rr->key->type)) |
2041 | continue; | |
2042 | ||
8e54f5d9 | 2043 | /* If this RR is in the negative trust anchor, we don't need to validate it. */ |
1c02e7ba | 2044 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(rr->key)); |
8e54f5d9 LP |
2045 | if (r < 0) |
2046 | return r; | |
2047 | if (r > 0) | |
2048 | continue; | |
2049 | ||
547973de LP |
2050 | switch (rr->key->type) { |
2051 | ||
2052 | case DNS_TYPE_RRSIG: { | |
2053 | /* For each RRSIG we request the matching DNSKEY */ | |
2054 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *dnskey = NULL; | |
2055 | ||
2056 | /* If this RRSIG is about a DNSKEY RR and the | |
2057 | * signer is the same as the owner, then we | |
2058 | * already have the DNSKEY, and we don't have | |
2059 | * to look for more. */ | |
2060 | if (rr->rrsig.type_covered == DNS_TYPE_DNSKEY) { | |
1c02e7ba | 2061 | r = dns_name_equal(rr->rrsig.signer, dns_resource_key_name(rr->key)); |
547973de LP |
2062 | if (r < 0) |
2063 | return r; | |
2064 | if (r > 0) | |
2065 | continue; | |
2066 | } | |
2067 | ||
105e1512 LP |
2068 | /* If the signer is not a parent of our |
2069 | * original query, then this is about an | |
2070 | * auxiliary RRset, but not anything we asked | |
2071 | * for. In this case we aren't interested, | |
2072 | * because we don't want to request additional | |
2073 | * RRs for stuff we didn't really ask for, and | |
2074 | * also to avoid request loops, where | |
2075 | * additional RRs from one transaction result | |
5238e957 | 2076 | * in another transaction whose additional RRs |
105e1512 LP |
2077 | * point back to the original transaction, and |
2078 | * we deadlock. */ | |
1c02e7ba | 2079 | r = dns_name_endswith(dns_resource_key_name(t->key), rr->rrsig.signer); |
547973de LP |
2080 | if (r < 0) |
2081 | return r; | |
2082 | if (r == 0) | |
2083 | continue; | |
2084 | ||
2085 | dnskey = dns_resource_key_new(rr->key->class, DNS_TYPE_DNSKEY, rr->rrsig.signer); | |
2086 | if (!dnskey) | |
2087 | return -ENOMEM; | |
2088 | ||
1c02e7ba ZJS |
2089 | log_debug("Requesting DNSKEY to validate transaction %" PRIu16" (%s, RRSIG with key tag: %" PRIu16 ").", |
2090 | t->id, dns_resource_key_name(rr->key), rr->rrsig.key_tag); | |
547973de LP |
2091 | r = dns_transaction_request_dnssec_rr(t, dnskey); |
2092 | if (r < 0) | |
2093 | return r; | |
2094 | break; | |
2095 | } | |
2096 | ||
2097 | case DNS_TYPE_DNSKEY: { | |
2098 | /* For each DNSKEY we request the matching DS */ | |
2099 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *ds = NULL; | |
2100 | ||
105e1512 LP |
2101 | /* If the DNSKEY we are looking at is not for |
2102 | * zone we are interested in, nor any of its | |
2103 | * parents, we aren't interested, and don't | |
2104 | * request it. After all, we don't want to end | |
2105 | * up in request loops, and want to keep | |
2106 | * additional traffic down. */ | |
2107 | ||
1c02e7ba | 2108 | r = dns_name_endswith(dns_resource_key_name(t->key), dns_resource_key_name(rr->key)); |
105e1512 LP |
2109 | if (r < 0) |
2110 | return r; | |
2111 | if (r == 0) | |
2112 | continue; | |
2113 | ||
1c02e7ba | 2114 | ds = dns_resource_key_new(rr->key->class, DNS_TYPE_DS, dns_resource_key_name(rr->key)); |
547973de LP |
2115 | if (!ds) |
2116 | return -ENOMEM; | |
2117 | ||
1c02e7ba ZJS |
2118 | log_debug("Requesting DS to validate transaction %" PRIu16" (%s, DNSKEY with key tag: %" PRIu16 ").", |
2119 | t->id, dns_resource_key_name(rr->key), dnssec_keytag(rr, false)); | |
105e1512 LP |
2120 | r = dns_transaction_request_dnssec_rr(t, ds); |
2121 | if (r < 0) | |
2122 | return r; | |
547973de | 2123 | |
105e1512 LP |
2124 | break; |
2125 | } | |
2126 | ||
105e1512 LP |
2127 | case DNS_TYPE_SOA: |
2128 | case DNS_TYPE_NS: { | |
2129 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *ds = NULL; | |
2130 | ||
2131 | /* For an unsigned SOA or NS, try to acquire | |
2132 | * the matching DS RR, as we are at a zone cut | |
2133 | * then, and whether a DS exists tells us | |
2134 | * whether the zone is signed. Do so only if | |
2135 | * this RR matches our original question, | |
2136 | * however. */ | |
2137 | ||
2138 | r = dns_resource_key_match_rr(t->key, rr, NULL); | |
2139 | if (r < 0) | |
2140 | return r; | |
6993d264 LP |
2141 | if (r == 0) { |
2142 | /* Hmm, so this SOA RR doesn't match our original question. In this case, maybe this is | |
2143 | * a negative reply, and we need the a SOA RR's TTL in order to cache a negative entry? | |
2144 | * If so, we need to validate it, too. */ | |
2145 | ||
2146 | r = dns_answer_match_key(t->answer, t->key, NULL); | |
2147 | if (r < 0) | |
2148 | return r; | |
2149 | if (r > 0) /* positive reply, we won't need the SOA and hence don't need to validate | |
2150 | * it. */ | |
2151 | continue; | |
d5acaa51 LP |
2152 | |
2153 | /* Only bother with this if the SOA/NS RR we are looking at is actually a parent of | |
2154 | * what we are looking for, otherwise there's no value in it for us. */ | |
2155 | r = dns_name_endswith(dns_resource_key_name(t->key), dns_resource_key_name(rr->key)); | |
2156 | if (r < 0) | |
2157 | return r; | |
2158 | if (r == 0) | |
2159 | continue; | |
6993d264 | 2160 | } |
105e1512 LP |
2161 | |
2162 | r = dnssec_has_rrsig(t->answer, rr->key); | |
2163 | if (r < 0) | |
2164 | return r; | |
2165 | if (r > 0) | |
2166 | continue; | |
2167 | ||
1c02e7ba | 2168 | ds = dns_resource_key_new(rr->key->class, DNS_TYPE_DS, dns_resource_key_name(rr->key)); |
105e1512 LP |
2169 | if (!ds) |
2170 | return -ENOMEM; | |
2171 | ||
1c02e7ba ZJS |
2172 | log_debug("Requesting DS to validate transaction %" PRIu16 " (%s, unsigned SOA/NS RRset).", |
2173 | t->id, dns_resource_key_name(rr->key)); | |
547973de LP |
2174 | r = dns_transaction_request_dnssec_rr(t, ds); |
2175 | if (r < 0) | |
2176 | return r; | |
2177 | ||
2178 | break; | |
105e1512 LP |
2179 | } |
2180 | ||
b63fca62 | 2181 | case DNS_TYPE_DS: |
105e1512 LP |
2182 | case DNS_TYPE_CNAME: |
2183 | case DNS_TYPE_DNAME: { | |
2184 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; | |
2185 | const char *name; | |
2186 | ||
2187 | /* CNAMEs and DNAMEs cannot be located at a | |
2188 | * zone apex, hence ask for the parent SOA for | |
2189 | * unsigned CNAME/DNAME RRs, maybe that's the | |
2190 | * apex. But do all that only if this is | |
2191 | * actually a response to our original | |
b63fca62 LP |
2192 | * question. |
2193 | * | |
2194 | * Similar for DS RRs, which are signed when | |
2195 | * the parent SOA is signed. */ | |
105e1512 LP |
2196 | |
2197 | r = dns_transaction_is_primary_response(t, rr); | |
2198 | if (r < 0) | |
2199 | return r; | |
2200 | if (r == 0) | |
2201 | continue; | |
2202 | ||
2203 | r = dnssec_has_rrsig(t->answer, rr->key); | |
2204 | if (r < 0) | |
2205 | return r; | |
2206 | if (r > 0) | |
2207 | continue; | |
2208 | ||
43e6779a LP |
2209 | r = dns_answer_has_dname_for_cname(t->answer, rr); |
2210 | if (r < 0) | |
2211 | return r; | |
2212 | if (r > 0) | |
2213 | continue; | |
2214 | ||
1c02e7ba | 2215 | name = dns_resource_key_name(rr->key); |
105e1512 LP |
2216 | r = dns_name_parent(&name); |
2217 | if (r < 0) | |
2218 | return r; | |
2219 | if (r == 0) | |
2220 | continue; | |
2221 | ||
2222 | soa = dns_resource_key_new(rr->key->class, DNS_TYPE_SOA, name); | |
2223 | if (!soa) | |
2224 | return -ENOMEM; | |
2225 | ||
1c02e7ba ZJS |
2226 | log_debug("Requesting parent SOA to validate transaction %" PRIu16 " (%s, unsigned CNAME/DNAME/DS RRset).", |
2227 | t->id, dns_resource_key_name(rr->key)); | |
105e1512 LP |
2228 | r = dns_transaction_request_dnssec_rr(t, soa); |
2229 | if (r < 0) | |
2230 | return r; | |
2231 | ||
2232 | break; | |
2233 | } | |
2234 | ||
2235 | default: { | |
2236 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; | |
2237 | ||
b63fca62 LP |
2238 | /* For other unsigned RRsets (including |
2239 | * NSEC/NSEC3!), look for proof the zone is | |
2240 | * unsigned, by requesting the SOA RR of the | |
2241 | * zone. However, do so only if they are | |
2242 | * directly relevant to our original | |
105e1512 LP |
2243 | * question. */ |
2244 | ||
2245 | r = dns_transaction_is_primary_response(t, rr); | |
2246 | if (r < 0) | |
2247 | return r; | |
2248 | if (r == 0) | |
2249 | continue; | |
2250 | ||
2251 | r = dnssec_has_rrsig(t->answer, rr->key); | |
2252 | if (r < 0) | |
2253 | return r; | |
2254 | if (r > 0) | |
2255 | continue; | |
2256 | ||
1c02e7ba | 2257 | soa = dns_resource_key_new(rr->key->class, DNS_TYPE_SOA, dns_resource_key_name(rr->key)); |
105e1512 LP |
2258 | if (!soa) |
2259 | return -ENOMEM; | |
2260 | ||
1c02e7ba ZJS |
2261 | log_debug("Requesting SOA to validate transaction %" PRIu16 " (%s, unsigned non-SOA/NS RRset <%s>).", |
2262 | t->id, dns_resource_key_name(rr->key), dns_resource_record_to_string(rr)); | |
105e1512 LP |
2263 | r = dns_transaction_request_dnssec_rr(t, soa); |
2264 | if (r < 0) | |
2265 | return r; | |
2266 | break; | |
547973de LP |
2267 | }} |
2268 | } | |
2269 | ||
105e1512 LP |
2270 | /* Above, we requested everything necessary to validate what |
2271 | * we got. Now, let's request what we need to validate what we | |
2272 | * didn't get... */ | |
2273 | ||
2274 | r = dns_transaction_has_unsigned_negative_answer(t); | |
2275 | if (r < 0) | |
2276 | return r; | |
2277 | if (r > 0) { | |
2278 | const char *name; | |
4bbc06cc | 2279 | uint16_t type = 0; |
105e1512 | 2280 | |
1c02e7ba | 2281 | name = dns_resource_key_name(t->key); |
105e1512 | 2282 | |
4bbc06cc LP |
2283 | /* If this was a SOA or NS request, then check if there's a DS RR for the same domain. Note that this |
2284 | * could also be used as indication that we are not at a zone apex, but in real world setups there are | |
2285 | * too many broken DNS servers (Hello, incapdns.net!) where non-terminal zones return NXDOMAIN even | |
2286 | * though they have further children. If this was a DS request, then it's signed when the parent zone | |
2287 | * is signed, hence ask the parent SOA in that case. If this was any other RR then ask for the SOA RR, | |
2288 | * to see if that is signed. */ | |
105e1512 | 2289 | |
4bbc06cc | 2290 | if (t->key->type == DNS_TYPE_DS) { |
105e1512 | 2291 | r = dns_name_parent(&name); |
4bbc06cc LP |
2292 | if (r > 0) { |
2293 | type = DNS_TYPE_SOA; | |
6d72da2f LP |
2294 | log_debug("Requesting parent SOA (→ %s) to validate transaction %" PRIu16 " (%s, unsigned empty DS response).", |
2295 | name, t->id, dns_resource_key_name(t->key)); | |
4bbc06cc | 2296 | } else |
105e1512 | 2297 | name = NULL; |
4bbc06cc LP |
2298 | |
2299 | } else if (IN_SET(t->key->type, DNS_TYPE_SOA, DNS_TYPE_NS)) { | |
2300 | ||
2301 | type = DNS_TYPE_DS; | |
6d72da2f LP |
2302 | log_debug("Requesting DS (→ %s) to validate transaction %" PRIu16 " (%s, unsigned empty SOA/NS response).", |
2303 | name, t->id, name); | |
4bbc06cc LP |
2304 | |
2305 | } else { | |
2306 | type = DNS_TYPE_SOA; | |
6d72da2f LP |
2307 | log_debug("Requesting SOA (→ %s) to validate transaction %" PRIu16 " (%s, unsigned empty non-SOA/NS/DS response).", |
2308 | name, t->id, name); | |
4bbc06cc | 2309 | } |
105e1512 LP |
2310 | |
2311 | if (name) { | |
2312 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *soa = NULL; | |
2313 | ||
4bbc06cc | 2314 | soa = dns_resource_key_new(t->key->class, type, name); |
105e1512 LP |
2315 | if (!soa) |
2316 | return -ENOMEM; | |
2317 | ||
2318 | r = dns_transaction_request_dnssec_rr(t, soa); | |
2319 | if (r < 0) | |
2320 | return r; | |
2321 | } | |
2322 | } | |
2323 | ||
2324 | return dns_transaction_dnssec_is_live(t); | |
547973de LP |
2325 | } |
2326 | ||
2327 | void dns_transaction_notify(DnsTransaction *t, DnsTransaction *source) { | |
547973de | 2328 | assert(t); |
547973de LP |
2329 | assert(source); |
2330 | ||
942eb2e7 LP |
2331 | /* Invoked whenever any of our auxiliary DNSSEC transactions completed its work. If the state is still PENDING, |
2332 | we are still in the loop that adds further DNSSEC transactions, hence don't check if we are ready yet. If | |
2333 | the state is VALIDATING however, we should check if we are complete now. */ | |
105e1512 | 2334 | |
942eb2e7 LP |
2335 | if (t->state == DNS_TRANSACTION_VALIDATING) |
2336 | dns_transaction_process_dnssec(t); | |
547973de LP |
2337 | } |
2338 | ||
105e1512 LP |
2339 | static int dns_transaction_validate_dnskey_by_ds(DnsTransaction *t) { |
2340 | DnsResourceRecord *rr; | |
2341 | int ifindex, r; | |
2342 | ||
2343 | assert(t); | |
2344 | ||
2345 | /* Add all DNSKEY RRs from the answer that are validated by DS | |
2346 | * RRs from the list of validated keys to the list of | |
2347 | * validated keys. */ | |
2348 | ||
2349 | DNS_ANSWER_FOREACH_IFINDEX(rr, ifindex, t->answer) { | |
2350 | ||
96bb7673 | 2351 | r = dnssec_verify_dnskey_by_ds_search(rr, t->validated_keys); |
105e1512 LP |
2352 | if (r < 0) |
2353 | return r; | |
2354 | if (r == 0) | |
2355 | continue; | |
2356 | ||
2357 | /* If so, the DNSKEY is validated too. */ | |
2358 | r = dns_answer_add_extend(&t->validated_keys, rr, ifindex, DNS_ANSWER_AUTHENTICATED); | |
2359 | if (r < 0) | |
2360 | return r; | |
2361 | } | |
2362 | ||
2363 | return 0; | |
2364 | } | |
2365 | ||
2366 | static int dns_transaction_requires_rrsig(DnsTransaction *t, DnsResourceRecord *rr) { | |
56352fe9 LP |
2367 | int r; |
2368 | ||
2369 | assert(t); | |
2370 | assert(rr); | |
2371 | ||
105e1512 LP |
2372 | /* Checks if the RR we are looking for must be signed with an |
2373 | * RRSIG. This is used for positive responses. */ | |
24a5b982 | 2374 | |
b652d4a2 | 2375 | if (t->scope->dnssec_mode == DNSSEC_NO) |
105e1512 | 2376 | return false; |
56352fe9 | 2377 | |
105e1512 LP |
2378 | if (dns_type_is_pseudo(rr->key->type)) |
2379 | return -EINVAL; | |
56352fe9 | 2380 | |
1c02e7ba | 2381 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(rr->key)); |
8e54f5d9 LP |
2382 | if (r < 0) |
2383 | return r; | |
2384 | if (r > 0) | |
2385 | return false; | |
2386 | ||
105e1512 | 2387 | switch (rr->key->type) { |
56352fe9 | 2388 | |
105e1512 LP |
2389 | case DNS_TYPE_RRSIG: |
2390 | /* RRSIGs are the signatures themselves, they need no signing. */ | |
2391 | return false; | |
2392 | ||
2393 | case DNS_TYPE_SOA: | |
2394 | case DNS_TYPE_NS: { | |
2395 | DnsTransaction *dt; | |
2396 | Iterator i; | |
2397 | ||
b63fca62 | 2398 | /* For SOA or NS RRs we look for a matching DS transaction */ |
105e1512 LP |
2399 | |
2400 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2401 | ||
2402 | if (dt->key->class != rr->key->class) | |
2403 | continue; | |
2404 | if (dt->key->type != DNS_TYPE_DS) | |
2405 | continue; | |
2406 | ||
1c02e7ba | 2407 | r = dns_name_equal(dns_resource_key_name(dt->key), dns_resource_key_name(rr->key)); |
105e1512 LP |
2408 | if (r < 0) |
2409 | return r; | |
2410 | if (r == 0) | |
2411 | continue; | |
2412 | ||
2413 | /* We found a DS transactions for the SOA/NS | |
2414 | * RRs we are looking at. If it discovered signed DS | |
2415 | * RRs, then we need to be signed, too. */ | |
2416 | ||
097a2517 TA |
2417 | if (!dt->answer_authenticated) |
2418 | return false; | |
105e1512 | 2419 | |
097a2517 | 2420 | return dns_answer_match_key(dt->answer, dt->key, NULL); |
105e1512 LP |
2421 | } |
2422 | ||
2423 | /* We found nothing that proves this is safe to leave | |
2424 | * this unauthenticated, hence ask inist on | |
2425 | * authentication. */ | |
2426 | return true; | |
2427 | } | |
2428 | ||
b63fca62 | 2429 | case DNS_TYPE_DS: |
105e1512 LP |
2430 | case DNS_TYPE_CNAME: |
2431 | case DNS_TYPE_DNAME: { | |
2432 | const char *parent = NULL; | |
2433 | DnsTransaction *dt; | |
2434 | Iterator i; | |
2435 | ||
b63fca62 LP |
2436 | /* |
2437 | * CNAME/DNAME RRs cannot be located at a zone apex, hence look directly for the parent SOA. | |
2438 | * | |
2439 | * DS RRs are signed if the parent is signed, hence also look at the parent SOA | |
2440 | */ | |
105e1512 LP |
2441 | |
2442 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2443 | ||
2444 | if (dt->key->class != rr->key->class) | |
2445 | continue; | |
2446 | if (dt->key->type != DNS_TYPE_SOA) | |
2447 | continue; | |
2448 | ||
2449 | if (!parent) { | |
1c02e7ba | 2450 | parent = dns_resource_key_name(rr->key); |
105e1512 LP |
2451 | r = dns_name_parent(&parent); |
2452 | if (r < 0) | |
2453 | return r; | |
2454 | if (r == 0) { | |
b63fca62 LP |
2455 | if (rr->key->type == DNS_TYPE_DS) |
2456 | return true; | |
2457 | ||
105e1512 | 2458 | /* A CNAME/DNAME without a parent? That's sooo weird. */ |
baaa35ad ZJS |
2459 | return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG), |
2460 | "Transaction %" PRIu16 " claims CNAME/DNAME at root. Refusing.", t->id); | |
105e1512 LP |
2461 | } |
2462 | } | |
2463 | ||
1c02e7ba | 2464 | r = dns_name_equal(dns_resource_key_name(dt->key), parent); |
105e1512 LP |
2465 | if (r < 0) |
2466 | return r; | |
2467 | if (r == 0) | |
2468 | continue; | |
2469 | ||
2470 | return t->answer_authenticated; | |
2471 | } | |
2472 | ||
2473 | return true; | |
2474 | } | |
2475 | ||
2476 | default: { | |
2477 | DnsTransaction *dt; | |
2478 | Iterator i; | |
2479 | ||
b63fca62 | 2480 | /* Any other kind of RR (including DNSKEY/NSEC/NSEC3). Let's see if our SOA lookup was authenticated */ |
105e1512 LP |
2481 | |
2482 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2483 | ||
2484 | if (dt->key->class != rr->key->class) | |
2485 | continue; | |
2486 | if (dt->key->type != DNS_TYPE_SOA) | |
2487 | continue; | |
2488 | ||
1c02e7ba | 2489 | r = dns_name_equal(dns_resource_key_name(dt->key), dns_resource_key_name(rr->key)); |
105e1512 LP |
2490 | if (r < 0) |
2491 | return r; | |
2492 | if (r == 0) | |
2493 | continue; | |
2494 | ||
2495 | /* We found the transaction that was supposed to find | |
2496 | * the SOA RR for us. It was successful, but found no | |
2497 | * RR for us. This means we are not at a zone cut. In | |
2498 | * this case, we require authentication if the SOA | |
2499 | * lookup was authenticated too. */ | |
2500 | return t->answer_authenticated; | |
2501 | } | |
2502 | ||
2503 | return true; | |
2504 | }} | |
56352fe9 LP |
2505 | } |
2506 | ||
d33b6cf3 LP |
2507 | static int dns_transaction_in_private_tld(DnsTransaction *t, const DnsResourceKey *key) { |
2508 | DnsTransaction *dt; | |
2509 | const char *tld; | |
2510 | Iterator i; | |
2511 | int r; | |
2512 | ||
2513 | /* If DNSSEC downgrade mode is on, checks whether the | |
2514 | * specified RR is one level below a TLD we have proven not to | |
2515 | * exist. In such a case we assume that this is a private | |
2516 | * domain, and permit it. | |
2517 | * | |
2518 | * This detects cases like the Fritz!Box router networks. Each | |
2519 | * Fritz!Box router serves a private "fritz.box" zone, in the | |
2520 | * non-existing TLD "box". Requests for the "fritz.box" domain | |
2521 | * are served by the router itself, while requests for the | |
2522 | * "box" domain will result in NXDOMAIN. | |
2523 | * | |
2524 | * Note that this logic is unable to detect cases where a | |
2525 | * router serves a private DNS zone directly under | |
2526 | * non-existing TLD. In such a case we cannot detect whether | |
2527 | * the TLD is supposed to exist or not, as all requests we | |
2528 | * make for it will be answered by the router's zone, and not | |
2529 | * by the root zone. */ | |
2530 | ||
2531 | assert(t); | |
2532 | ||
2533 | if (t->scope->dnssec_mode != DNSSEC_ALLOW_DOWNGRADE) | |
2534 | return false; /* In strict DNSSEC mode what doesn't exist, doesn't exist */ | |
2535 | ||
1c02e7ba | 2536 | tld = dns_resource_key_name(key); |
d33b6cf3 LP |
2537 | r = dns_name_parent(&tld); |
2538 | if (r < 0) | |
2539 | return r; | |
2540 | if (r == 0) | |
2541 | return false; /* Already the root domain */ | |
2542 | ||
2543 | if (!dns_name_is_single_label(tld)) | |
2544 | return false; | |
2545 | ||
2546 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2547 | ||
2548 | if (dt->key->class != key->class) | |
2549 | continue; | |
2550 | ||
1c02e7ba | 2551 | r = dns_name_equal(dns_resource_key_name(dt->key), tld); |
d33b6cf3 LP |
2552 | if (r < 0) |
2553 | return r; | |
2554 | if (r == 0) | |
2555 | continue; | |
2556 | ||
2557 | /* We found an auxiliary lookup we did for the TLD. If | |
2558 | * that returned with NXDOMAIN, we know the TLD didn't | |
2559 | * exist, and hence this might be a private zone. */ | |
2560 | ||
2561 | return dt->answer_rcode == DNS_RCODE_NXDOMAIN; | |
2562 | } | |
2563 | ||
2564 | return false; | |
2565 | } | |
2566 | ||
105e1512 | 2567 | static int dns_transaction_requires_nsec(DnsTransaction *t) { |
4bbc06cc | 2568 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
105e1512 LP |
2569 | DnsTransaction *dt; |
2570 | const char *name; | |
4bbc06cc | 2571 | uint16_t type = 0; |
105e1512 LP |
2572 | Iterator i; |
2573 | int r; | |
56352fe9 LP |
2574 | |
2575 | assert(t); | |
2576 | ||
105e1512 LP |
2577 | /* Checks if we need to insist on NSEC/NSEC3 RRs for proving |
2578 | * this negative reply */ | |
56352fe9 | 2579 | |
b652d4a2 | 2580 | if (t->scope->dnssec_mode == DNSSEC_NO) |
105e1512 | 2581 | return false; |
56352fe9 | 2582 | |
105e1512 LP |
2583 | if (dns_type_is_pseudo(t->key->type)) |
2584 | return -EINVAL; | |
2585 | ||
1c02e7ba | 2586 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(t->key)); |
8e54f5d9 LP |
2587 | if (r < 0) |
2588 | return r; | |
2589 | if (r > 0) | |
2590 | return false; | |
2591 | ||
d33b6cf3 LP |
2592 | r = dns_transaction_in_private_tld(t, t->key); |
2593 | if (r < 0) | |
2594 | return r; | |
2595 | if (r > 0) { | |
2596 | /* The lookup is from a TLD that is proven not to | |
2597 | * exist, and we are in downgrade mode, hence ignore | |
13e785f7 | 2598 | * that fact that we didn't get any NSEC RRs. */ |
d33b6cf3 | 2599 | |
202b76ae ZJS |
2600 | log_info("Detected a negative query %s in a private DNS zone, permitting unsigned response.", |
2601 | dns_resource_key_to_string(t->key, key_str, sizeof key_str)); | |
d33b6cf3 LP |
2602 | return false; |
2603 | } | |
2604 | ||
1c02e7ba | 2605 | name = dns_resource_key_name(t->key); |
105e1512 | 2606 | |
4bbc06cc | 2607 | if (t->key->type == DNS_TYPE_DS) { |
105e1512 | 2608 | |
4bbc06cc LP |
2609 | /* We got a negative reply for this DS lookup? DS RRs are signed when their parent zone is signed, |
2610 | * hence check the parent SOA in this case. */ | |
105e1512 LP |
2611 | |
2612 | r = dns_name_parent(&name); | |
56352fe9 LP |
2613 | if (r < 0) |
2614 | return r; | |
2615 | if (r == 0) | |
105e1512 | 2616 | return true; |
4bbc06cc LP |
2617 | |
2618 | type = DNS_TYPE_SOA; | |
2619 | ||
2620 | } else if (IN_SET(t->key->type, DNS_TYPE_SOA, DNS_TYPE_NS)) | |
2621 | /* We got a negative reply for this SOA/NS lookup? If so, check if there's a DS RR for this */ | |
2622 | type = DNS_TYPE_DS; | |
2623 | else | |
2624 | /* For all other negative replies, check for the SOA lookup */ | |
2625 | type = DNS_TYPE_SOA; | |
105e1512 LP |
2626 | |
2627 | /* For all other RRs we check the SOA on the same level to see | |
2628 | * if it's signed. */ | |
2629 | ||
2630 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2631 | ||
2632 | if (dt->key->class != t->key->class) | |
2633 | continue; | |
4bbc06cc | 2634 | if (dt->key->type != type) |
56352fe9 LP |
2635 | continue; |
2636 | ||
1c02e7ba | 2637 | r = dns_name_equal(dns_resource_key_name(dt->key), name); |
56352fe9 LP |
2638 | if (r < 0) |
2639 | return r; | |
105e1512 LP |
2640 | if (r == 0) |
2641 | continue; | |
2642 | ||
2643 | return dt->answer_authenticated; | |
56352fe9 LP |
2644 | } |
2645 | ||
105e1512 LP |
2646 | /* If in doubt, require NSEC/NSEC3 */ |
2647 | return true; | |
56352fe9 LP |
2648 | } |
2649 | ||
94aa7071 LP |
2650 | static int dns_transaction_dnskey_authenticated(DnsTransaction *t, DnsResourceRecord *rr) { |
2651 | DnsResourceRecord *rrsig; | |
2652 | bool found = false; | |
2653 | int r; | |
2654 | ||
2655 | /* Checks whether any of the DNSKEYs used for the RRSIGs for | |
2656 | * the specified RRset is authenticated (i.e. has a matching | |
2657 | * DS RR). */ | |
2658 | ||
1c02e7ba | 2659 | r = dns_transaction_negative_trust_anchor_lookup(t, dns_resource_key_name(rr->key)); |
8e54f5d9 LP |
2660 | if (r < 0) |
2661 | return r; | |
2662 | if (r > 0) | |
2663 | return false; | |
2664 | ||
94aa7071 LP |
2665 | DNS_ANSWER_FOREACH(rrsig, t->answer) { |
2666 | DnsTransaction *dt; | |
2667 | Iterator i; | |
2668 | ||
2669 | r = dnssec_key_match_rrsig(rr->key, rrsig); | |
2670 | if (r < 0) | |
2671 | return r; | |
2672 | if (r == 0) | |
2673 | continue; | |
2674 | ||
2675 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2676 | ||
2677 | if (dt->key->class != rr->key->class) | |
2678 | continue; | |
2679 | ||
2680 | if (dt->key->type == DNS_TYPE_DNSKEY) { | |
2681 | ||
1c02e7ba | 2682 | r = dns_name_equal(dns_resource_key_name(dt->key), rrsig->rrsig.signer); |
94aa7071 LP |
2683 | if (r < 0) |
2684 | return r; | |
2685 | if (r == 0) | |
2686 | continue; | |
2687 | ||
2688 | /* OK, we found an auxiliary DNSKEY | |
2689 | * lookup. If that lookup is | |
2690 | * authenticated, report this. */ | |
2691 | ||
2692 | if (dt->answer_authenticated) | |
2693 | return true; | |
2694 | ||
2695 | found = true; | |
2696 | ||
2697 | } else if (dt->key->type == DNS_TYPE_DS) { | |
2698 | ||
1c02e7ba | 2699 | r = dns_name_equal(dns_resource_key_name(dt->key), rrsig->rrsig.signer); |
94aa7071 LP |
2700 | if (r < 0) |
2701 | return r; | |
2702 | if (r == 0) | |
2703 | continue; | |
2704 | ||
2705 | /* OK, we found an auxiliary DS | |
2706 | * lookup. If that lookup is | |
2707 | * authenticated and non-zero, we | |
2708 | * won! */ | |
2709 | ||
2710 | if (!dt->answer_authenticated) | |
2711 | return false; | |
2712 | ||
2713 | return dns_answer_match_key(dt->answer, dt->key, NULL); | |
2714 | } | |
2715 | } | |
2716 | } | |
2717 | ||
2718 | return found ? false : -ENXIO; | |
2719 | } | |
2720 | ||
b652d4a2 LP |
2721 | static int dns_transaction_known_signed(DnsTransaction *t, DnsResourceRecord *rr) { |
2722 | assert(t); | |
2723 | assert(rr); | |
2724 | ||
2725 | /* We know that the root domain is signed, hence if it appears | |
2726 | * not to be signed, there's a problem with the DNS server */ | |
2727 | ||
2728 | return rr->key->class == DNS_CLASS_IN && | |
1c02e7ba | 2729 | dns_name_is_root(dns_resource_key_name(rr->key)); |
b652d4a2 LP |
2730 | } |
2731 | ||
0f87f3e8 LP |
2732 | static int dns_transaction_check_revoked_trust_anchors(DnsTransaction *t) { |
2733 | DnsResourceRecord *rr; | |
2734 | int r; | |
2735 | ||
2736 | assert(t); | |
2737 | ||
2738 | /* Maybe warn the user that we encountered a revoked DNSKEY | |
2739 | * for a key from our trust anchor. Note that we don't care | |
2740 | * whether the DNSKEY can be authenticated or not. It's | |
2741 | * sufficient if it is self-signed. */ | |
2742 | ||
2743 | DNS_ANSWER_FOREACH(rr, t->answer) { | |
d424da2a | 2744 | r = dns_trust_anchor_check_revoked(&t->scope->manager->trust_anchor, rr, t->answer); |
0f87f3e8 LP |
2745 | if (r < 0) |
2746 | return r; | |
2747 | } | |
2748 | ||
2749 | return 0; | |
2750 | } | |
2751 | ||
c9c72065 LP |
2752 | static int dns_transaction_invalidate_revoked_keys(DnsTransaction *t) { |
2753 | bool changed; | |
2754 | int r; | |
2755 | ||
2756 | assert(t); | |
2757 | ||
2758 | /* Removes all DNSKEY/DS objects from t->validated_keys that | |
2759 | * our trust anchors database considers revoked. */ | |
2760 | ||
2761 | do { | |
2762 | DnsResourceRecord *rr; | |
2763 | ||
2764 | changed = false; | |
2765 | ||
2766 | DNS_ANSWER_FOREACH(rr, t->validated_keys) { | |
2767 | r = dns_trust_anchor_is_revoked(&t->scope->manager->trust_anchor, rr); | |
2768 | if (r < 0) | |
2769 | return r; | |
2770 | if (r > 0) { | |
2771 | r = dns_answer_remove_by_rr(&t->validated_keys, rr); | |
2772 | if (r < 0) | |
2773 | return r; | |
2774 | ||
2775 | assert(r > 0); | |
2776 | changed = true; | |
2777 | break; | |
2778 | } | |
2779 | } | |
2780 | } while (changed); | |
2781 | ||
2782 | return 0; | |
2783 | } | |
2784 | ||
942eb2e7 LP |
2785 | static int dns_transaction_copy_validated(DnsTransaction *t) { |
2786 | DnsTransaction *dt; | |
2787 | Iterator i; | |
2788 | int r; | |
2789 | ||
2790 | assert(t); | |
2791 | ||
2792 | /* Copy all validated RRs from the auxiliary DNSSEC transactions into our set of validated RRs */ | |
2793 | ||
2794 | SET_FOREACH(dt, t->dnssec_transactions, i) { | |
2795 | ||
2796 | if (DNS_TRANSACTION_IS_LIVE(dt->state)) | |
2797 | continue; | |
2798 | ||
2799 | if (!dt->answer_authenticated) | |
2800 | continue; | |
2801 | ||
2802 | r = dns_answer_extend(&t->validated_keys, dt->answer); | |
2803 | if (r < 0) | |
2804 | return r; | |
2805 | } | |
2806 | ||
2807 | return 0; | |
2808 | } | |
2809 | ||
c690b20a ZJS |
2810 | typedef enum { |
2811 | DNSSEC_PHASE_DNSKEY, /* Phase #1, only validate DNSKEYs */ | |
2812 | DNSSEC_PHASE_NSEC, /* Phase #2, only validate NSEC+NSEC3 */ | |
2813 | DNSSEC_PHASE_ALL, /* Phase #3, validate everything else */ | |
2814 | } Phase; | |
2815 | ||
2816 | static int dnssec_validate_records( | |
2817 | DnsTransaction *t, | |
2818 | Phase phase, | |
2819 | bool *have_nsec, | |
2820 | DnsAnswer **validated) { | |
2821 | ||
547973de | 2822 | DnsResourceRecord *rr; |
56352fe9 | 2823 | int r; |
547973de | 2824 | |
c690b20a | 2825 | /* Returns negative on error, 0 if validation failed, 1 to restart validation, 2 when finished. */ |
547973de | 2826 | |
c690b20a ZJS |
2827 | DNS_ANSWER_FOREACH(rr, t->answer) { |
2828 | DnsResourceRecord *rrsig = NULL; | |
2829 | DnssecResult result; | |
547973de | 2830 | |
c690b20a ZJS |
2831 | switch (rr->key->type) { |
2832 | case DNS_TYPE_RRSIG: | |
2833 | continue; | |
547973de | 2834 | |
c690b20a ZJS |
2835 | case DNS_TYPE_DNSKEY: |
2836 | /* We validate DNSKEYs only in the DNSKEY and ALL phases */ | |
2837 | if (phase == DNSSEC_PHASE_NSEC) | |
2838 | continue; | |
2839 | break; | |
547973de | 2840 | |
c690b20a ZJS |
2841 | case DNS_TYPE_NSEC: |
2842 | case DNS_TYPE_NSEC3: | |
2843 | *have_nsec = true; | |
547973de | 2844 | |
c690b20a ZJS |
2845 | /* We validate NSEC/NSEC3 only in the NSEC and ALL phases */ |
2846 | if (phase == DNSSEC_PHASE_DNSKEY) | |
2847 | continue; | |
2848 | break; | |
105e1512 | 2849 | |
c690b20a ZJS |
2850 | default: |
2851 | /* We validate all other RRs only in the ALL phases */ | |
2852 | if (phase != DNSSEC_PHASE_ALL) | |
2853 | continue; | |
2854 | } | |
b652d4a2 | 2855 | |
c690b20a ZJS |
2856 | r = dnssec_verify_rrset_search(t->answer, rr->key, t->validated_keys, USEC_INFINITY, &result, &rrsig); |
2857 | if (r < 0) | |
2858 | return r; | |
547973de | 2859 | |
c690b20a | 2860 | log_debug("Looking at %s: %s", strna(dns_resource_record_to_string(rr)), dnssec_result_to_string(result)); |
0f87f3e8 | 2861 | |
c690b20a | 2862 | if (result == DNSSEC_VALIDATED) { |
942eb2e7 | 2863 | |
c690b20a ZJS |
2864 | if (rr->key->type == DNS_TYPE_DNSKEY) { |
2865 | /* If we just validated a DNSKEY RRset, then let's add these keys to | |
2866 | * the set of validated keys for this transaction. */ | |
547973de | 2867 | |
c690b20a ZJS |
2868 | r = dns_answer_copy_by_key(&t->validated_keys, t->answer, rr->key, DNS_ANSWER_AUTHENTICATED); |
2869 | if (r < 0) | |
2870 | return r; | |
c9c72065 | 2871 | |
c690b20a ZJS |
2872 | /* Some of the DNSKEYs we just added might already have been revoked, |
2873 | * remove them again in that case. */ | |
2874 | r = dns_transaction_invalidate_revoked_keys(t); | |
2875 | if (r < 0) | |
2876 | return r; | |
2877 | } | |
547973de | 2878 | |
c690b20a ZJS |
2879 | /* Add the validated RRset to the new list of validated |
2880 | * RRsets, and remove it from the unvalidated RRsets. | |
2881 | * We mark the RRset as authenticated and cacheable. */ | |
2882 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, DNS_ANSWER_AUTHENTICATED|DNS_ANSWER_CACHEABLE); | |
2883 | if (r < 0) | |
2884 | return r; | |
547973de | 2885 | |
c690b20a | 2886 | manager_dnssec_verdict(t->scope->manager, DNSSEC_SECURE, rr->key); |
0c7bff0a | 2887 | |
c690b20a ZJS |
2888 | /* Exit the loop, we dropped something from the answer, start from the beginning */ |
2889 | return 1; | |
2890 | } | |
547973de | 2891 | |
c690b20a ZJS |
2892 | /* If we haven't read all DNSKEYs yet a negative result of the validation is irrelevant, as |
2893 | * there might be more DNSKEYs coming. Similar, if we haven't read all NSEC/NSEC3 RRs yet, | |
2894 | * we cannot do positive wildcard proofs yet, as those require the NSEC/NSEC3 RRs. */ | |
2895 | if (phase != DNSSEC_PHASE_ALL) | |
2896 | continue; | |
0c7bff0a | 2897 | |
c690b20a ZJS |
2898 | if (result == DNSSEC_VALIDATED_WILDCARD) { |
2899 | bool authenticated = false; | |
2900 | const char *source; | |
0c7bff0a | 2901 | |
c690b20a | 2902 | /* This RRset validated, but as a wildcard. This means we need |
13e785f7 | 2903 | * to prove via NSEC/NSEC3 that no matching non-wildcard RR exists. */ |
0c7bff0a | 2904 | |
c690b20a ZJS |
2905 | /* First step, determine the source of synthesis */ |
2906 | r = dns_resource_record_source(rrsig, &source); | |
2907 | if (r < 0) | |
2908 | return r; | |
0c7bff0a | 2909 | |
c690b20a | 2910 | r = dnssec_test_positive_wildcard(*validated, |
1c02e7ba | 2911 | dns_resource_key_name(rr->key), |
c690b20a ZJS |
2912 | source, |
2913 | rrsig->rrsig.signer, | |
2914 | &authenticated); | |
0c7bff0a | 2915 | |
c690b20a ZJS |
2916 | /* Unless the NSEC proof showed that the key really doesn't exist something is off. */ |
2917 | if (r == 0) | |
2918 | result = DNSSEC_INVALID; | |
2919 | else { | |
2920 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, | |
2921 | authenticated ? (DNS_ANSWER_AUTHENTICATED|DNS_ANSWER_CACHEABLE) : 0); | |
2922 | if (r < 0) | |
2923 | return r; | |
2924 | ||
2925 | manager_dnssec_verdict(t->scope->manager, authenticated ? DNSSEC_SECURE : DNSSEC_INSECURE, rr->key); | |
2926 | ||
2927 | /* Exit the loop, we dropped something from the answer, start from the beginning */ | |
2928 | return 1; | |
0c7bff0a | 2929 | } |
c690b20a | 2930 | } |
0c7bff0a | 2931 | |
c690b20a ZJS |
2932 | if (result == DNSSEC_NO_SIGNATURE) { |
2933 | r = dns_transaction_requires_rrsig(t, rr); | |
547973de LP |
2934 | if (r < 0) |
2935 | return r; | |
c690b20a ZJS |
2936 | if (r == 0) { |
2937 | /* Data does not require signing. In that case, just copy it over, | |
13e785f7 | 2938 | * but remember that this is by no means authenticated. */ |
c690b20a ZJS |
2939 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); |
2940 | if (r < 0) | |
2941 | return r; | |
2942 | ||
2943 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); | |
2944 | return 1; | |
2945 | } | |
547973de | 2946 | |
c690b20a ZJS |
2947 | r = dns_transaction_known_signed(t, rr); |
2948 | if (r < 0) | |
2949 | return r; | |
2950 | if (r > 0) { | |
2951 | /* This is an RR we know has to be signed. If it isn't this means | |
2952 | * the server is not attaching RRSIGs, hence complain. */ | |
547973de | 2953 | |
c690b20a | 2954 | dns_server_packet_rrsig_missing(t->server, t->current_feature_level); |
547973de | 2955 | |
c690b20a | 2956 | if (t->scope->dnssec_mode == DNSSEC_ALLOW_DOWNGRADE) { |
547973de | 2957 | |
c690b20a | 2958 | /* Downgrading is OK? If so, just consider the information unsigned */ |
c9c72065 | 2959 | |
c690b20a | 2960 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); |
c9c72065 LP |
2961 | if (r < 0) |
2962 | return r; | |
547973de | 2963 | |
c690b20a ZJS |
2964 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); |
2965 | return 1; | |
2966 | } | |
a150ff5e | 2967 | |
c690b20a ZJS |
2968 | /* Otherwise, fail */ |
2969 | t->answer_dnssec_result = DNSSEC_INCOMPATIBLE_SERVER; | |
2970 | return 0; | |
f3cf586d | 2971 | } |
547973de | 2972 | |
c690b20a ZJS |
2973 | r = dns_transaction_in_private_tld(t, rr->key); |
2974 | if (r < 0) | |
2975 | return r; | |
2976 | if (r > 0) { | |
202b76ae | 2977 | char s[DNS_RESOURCE_KEY_STRING_MAX]; |
b652d4a2 | 2978 | |
c690b20a ZJS |
2979 | /* The data is from a TLD that is proven not to exist, and we are in downgrade |
2980 | * mode, hence ignore the fact that this was not signed. */ | |
0c7bff0a | 2981 | |
202b76ae ZJS |
2982 | log_info("Detected RRset %s is in a private DNS zone, permitting unsigned RRs.", |
2983 | dns_resource_key_to_string(rr->key, s, sizeof s)); | |
0c7bff0a | 2984 | |
c690b20a | 2985 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); |
0c7bff0a LP |
2986 | if (r < 0) |
2987 | return r; | |
0c7bff0a | 2988 | |
c690b20a ZJS |
2989 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); |
2990 | return 1; | |
2991 | } | |
2992 | } | |
0c7bff0a | 2993 | |
c690b20a ZJS |
2994 | if (IN_SET(result, |
2995 | DNSSEC_MISSING_KEY, | |
2996 | DNSSEC_SIGNATURE_EXPIRED, | |
2997 | DNSSEC_UNSUPPORTED_ALGORITHM)) { | |
0c7bff0a | 2998 | |
c690b20a ZJS |
2999 | r = dns_transaction_dnskey_authenticated(t, rr); |
3000 | if (r < 0 && r != -ENXIO) | |
3001 | return r; | |
3002 | if (r == 0) { | |
3003 | /* The DNSKEY transaction was not authenticated, this means there's | |
3004 | * no DS for this, which means it's OK if no keys are found for this signature. */ | |
0c7bff0a | 3005 | |
c690b20a | 3006 | r = dns_answer_move_by_key(validated, &t->answer, rr->key, 0); |
f3cf586d LP |
3007 | if (r < 0) |
3008 | return r; | |
b652d4a2 | 3009 | |
c690b20a ZJS |
3010 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, rr->key); |
3011 | return 1; | |
3012 | } | |
3013 | } | |
b652d4a2 | 3014 | |
c690b20a ZJS |
3015 | r = dns_transaction_is_primary_response(t, rr); |
3016 | if (r < 0) | |
3017 | return r; | |
3018 | if (r > 0) { | |
3019 | /* Look for a matching DNAME for this CNAME */ | |
3020 | r = dns_answer_has_dname_for_cname(t->answer, rr); | |
3021 | if (r < 0) | |
3022 | return r; | |
3023 | if (r == 0) { | |
3024 | /* Also look among the stuff we already validated */ | |
3025 | r = dns_answer_has_dname_for_cname(*validated, rr); | |
f3cf586d LP |
3026 | if (r < 0) |
3027 | return r; | |
c690b20a | 3028 | } |
d33b6cf3 | 3029 | |
c690b20a ZJS |
3030 | if (r == 0) { |
3031 | if (IN_SET(result, | |
3032 | DNSSEC_INVALID, | |
3033 | DNSSEC_SIGNATURE_EXPIRED, | |
3034 | DNSSEC_NO_SIGNATURE)) | |
3035 | manager_dnssec_verdict(t->scope->manager, DNSSEC_BOGUS, rr->key); | |
3036 | else /* DNSSEC_MISSING_KEY or DNSSEC_UNSUPPORTED_ALGORITHM */ | |
3037 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INDETERMINATE, rr->key); | |
3038 | ||
3039 | /* This is a primary response to our question, and it failed validation. | |
3040 | * That's fatal. */ | |
3041 | t->answer_dnssec_result = result; | |
3042 | return 0; | |
3043 | } | |
d33b6cf3 | 3044 | |
c690b20a ZJS |
3045 | /* This is a primary response, but we do have a DNAME RR |
3046 | * in the RR that can replay this CNAME, hence rely on | |
3047 | * that, and we can remove the CNAME in favour of it. */ | |
3048 | } | |
d33b6cf3 | 3049 | |
c690b20a ZJS |
3050 | /* This is just some auxiliary data. Just remove the RRset and continue. */ |
3051 | r = dns_answer_remove_by_key(&t->answer, rr->key); | |
3052 | if (r < 0) | |
3053 | return r; | |
d33b6cf3 | 3054 | |
c690b20a ZJS |
3055 | /* We dropped something from the answer, start from the beginning. */ |
3056 | return 1; | |
3057 | } | |
f3cf586d | 3058 | |
c690b20a ZJS |
3059 | return 2; /* Finito. */ |
3060 | } | |
94aa7071 | 3061 | |
c690b20a ZJS |
3062 | int dns_transaction_validate_dnssec(DnsTransaction *t) { |
3063 | _cleanup_(dns_answer_unrefp) DnsAnswer *validated = NULL; | |
3064 | Phase phase; | |
3065 | DnsAnswerFlags flags; | |
3066 | int r; | |
202b76ae | 3067 | char key_str[DNS_RESOURCE_KEY_STRING_MAX]; |
94aa7071 | 3068 | |
c690b20a | 3069 | assert(t); |
94aa7071 | 3070 | |
c690b20a ZJS |
3071 | /* We have now collected all DS and DNSKEY RRs in |
3072 | * t->validated_keys, let's see which RRs we can now | |
3073 | * authenticate with that. */ | |
94aa7071 | 3074 | |
c690b20a ZJS |
3075 | if (t->scope->dnssec_mode == DNSSEC_NO) |
3076 | return 0; | |
a150ff5e | 3077 | |
c690b20a ZJS |
3078 | /* Already validated */ |
3079 | if (t->answer_dnssec_result != _DNSSEC_RESULT_INVALID) | |
3080 | return 0; | |
105e1512 | 3081 | |
c690b20a ZJS |
3082 | /* Our own stuff needs no validation */ |
3083 | if (IN_SET(t->answer_source, DNS_TRANSACTION_ZONE, DNS_TRANSACTION_TRUST_ANCHOR)) { | |
3084 | t->answer_dnssec_result = DNSSEC_VALIDATED; | |
3085 | t->answer_authenticated = true; | |
3086 | return 0; | |
3087 | } | |
a150ff5e | 3088 | |
c690b20a ZJS |
3089 | /* Cached stuff is not affected by validation. */ |
3090 | if (t->answer_source != DNS_TRANSACTION_NETWORK) | |
3091 | return 0; | |
f3cf586d | 3092 | |
c690b20a ZJS |
3093 | if (!dns_transaction_dnssec_supported_full(t)) { |
3094 | /* The server does not support DNSSEC, or doesn't augment responses with RRSIGs. */ | |
3095 | t->answer_dnssec_result = DNSSEC_INCOMPATIBLE_SERVER; | |
d001e0a3 | 3096 | log_debug("Not validating response for %" PRIu16 ", used server feature level does not support DNSSEC.", t->id); |
c690b20a ZJS |
3097 | return 0; |
3098 | } | |
f3cf586d | 3099 | |
202b76ae ZJS |
3100 | log_debug("Validating response from transaction %" PRIu16 " (%s).", |
3101 | t->id, | |
3102 | dns_resource_key_to_string(t->key, key_str, sizeof key_str)); | |
547973de | 3103 | |
c690b20a ZJS |
3104 | /* First, see if this response contains any revoked trust |
3105 | * anchors we care about */ | |
3106 | r = dns_transaction_check_revoked_trust_anchors(t); | |
3107 | if (r < 0) | |
3108 | return r; | |
43e6779a | 3109 | |
c690b20a ZJS |
3110 | /* Third, copy all RRs we acquired successfully from auxiliary RRs over. */ |
3111 | r = dns_transaction_copy_validated(t); | |
3112 | if (r < 0) | |
3113 | return r; | |
43e6779a | 3114 | |
c690b20a ZJS |
3115 | /* Second, see if there are DNSKEYs we already know a |
3116 | * validated DS for. */ | |
3117 | r = dns_transaction_validate_dnskey_by_ds(t); | |
3118 | if (r < 0) | |
3119 | return r; | |
43e6779a | 3120 | |
c690b20a ZJS |
3121 | /* Fourth, remove all DNSKEY and DS RRs again that our trust |
3122 | * anchor says are revoked. After all we might have marked | |
3123 | * some keys revoked above, but they might still be lingering | |
3124 | * in our validated_keys list. */ | |
3125 | r = dns_transaction_invalidate_revoked_keys(t); | |
3126 | if (r < 0) | |
3127 | return r; | |
f3cf586d | 3128 | |
c690b20a ZJS |
3129 | phase = DNSSEC_PHASE_DNSKEY; |
3130 | for (;;) { | |
3131 | bool have_nsec = false; | |
f3cf586d | 3132 | |
c690b20a ZJS |
3133 | r = dnssec_validate_records(t, phase, &have_nsec, &validated); |
3134 | if (r <= 0) | |
3135 | return r; | |
547973de | 3136 | |
c690b20a ZJS |
3137 | /* Try again as long as we managed to achieve something */ |
3138 | if (r == 1) | |
547973de LP |
3139 | continue; |
3140 | ||
c690b20a | 3141 | if (phase == DNSSEC_PHASE_DNSKEY && have_nsec) { |
0c7bff0a | 3142 | /* OK, we processed all DNSKEYs, and there are NSEC/NSEC3 RRs, look at those now. */ |
c690b20a | 3143 | phase = DNSSEC_PHASE_NSEC; |
0c7bff0a LP |
3144 | continue; |
3145 | } | |
3146 | ||
c690b20a ZJS |
3147 | if (phase != DNSSEC_PHASE_ALL) { |
3148 | /* OK, we processed all DNSKEYs and NSEC/NSEC3 RRs, look at all the rest now. | |
3149 | * Note that in this third phase we start to remove RRs we couldn't validate. */ | |
3150 | phase = DNSSEC_PHASE_ALL; | |
56352fe9 | 3151 | continue; |
547973de LP |
3152 | } |
3153 | ||
56352fe9 | 3154 | /* We're done */ |
547973de LP |
3155 | break; |
3156 | } | |
3157 | ||
3158 | dns_answer_unref(t->answer); | |
1cc6c93a | 3159 | t->answer = TAKE_PTR(validated); |
547973de | 3160 | |
72667f08 LP |
3161 | /* At this point the answer only contains validated |
3162 | * RRsets. Now, let's see if it actually answers the question | |
3163 | * we asked. If so, great! If it doesn't, then see if | |
3164 | * NSEC/NSEC3 can prove this. */ | |
105e1512 | 3165 | r = dns_transaction_has_positive_answer(t, &flags); |
72667f08 | 3166 | if (r > 0) { |
105e1512 LP |
3167 | /* Yes, it answers the question! */ |
3168 | ||
3169 | if (flags & DNS_ANSWER_AUTHENTICATED) { | |
3170 | /* The answer is fully authenticated, yay. */ | |
019036a4 | 3171 | t->answer_dnssec_result = DNSSEC_VALIDATED; |
105e1512 LP |
3172 | t->answer_rcode = DNS_RCODE_SUCCESS; |
3173 | t->answer_authenticated = true; | |
3174 | } else { | |
3175 | /* The answer is not fully authenticated. */ | |
019036a4 | 3176 | t->answer_dnssec_result = DNSSEC_UNSIGNED; |
105e1512 LP |
3177 | t->answer_authenticated = false; |
3178 | } | |
3179 | ||
72667f08 LP |
3180 | } else if (r == 0) { |
3181 | DnssecNsecResult nr; | |
ed29bfdc | 3182 | bool authenticated = false; |
72667f08 LP |
3183 | |
3184 | /* Bummer! Let's check NSEC/NSEC3 */ | |
0c7bff0a | 3185 | r = dnssec_nsec_test(t->answer, t->key, &nr, &authenticated, &t->answer_nsec_ttl); |
72667f08 LP |
3186 | if (r < 0) |
3187 | return r; | |
3188 | ||
3189 | switch (nr) { | |
3190 | ||
3191 | case DNSSEC_NSEC_NXDOMAIN: | |
3192 | /* NSEC proves the domain doesn't exist. Very good. */ | |
202b76ae | 3193 | log_debug("Proved NXDOMAIN via NSEC/NSEC3 for transaction %u (%s)", t->id, key_str); |
019036a4 | 3194 | t->answer_dnssec_result = DNSSEC_VALIDATED; |
72667f08 | 3195 | t->answer_rcode = DNS_RCODE_NXDOMAIN; |
ed29bfdc | 3196 | t->answer_authenticated = authenticated; |
7aa8ce98 | 3197 | |
59c5b597 | 3198 | manager_dnssec_verdict(t->scope->manager, authenticated ? DNSSEC_SECURE : DNSSEC_INSECURE, t->key); |
72667f08 LP |
3199 | break; |
3200 | ||
3201 | case DNSSEC_NSEC_NODATA: | |
3202 | /* NSEC proves that there's no data here, very good. */ | |
202b76ae | 3203 | log_debug("Proved NODATA via NSEC/NSEC3 for transaction %u (%s)", t->id, key_str); |
019036a4 | 3204 | t->answer_dnssec_result = DNSSEC_VALIDATED; |
72667f08 | 3205 | t->answer_rcode = DNS_RCODE_SUCCESS; |
ed29bfdc | 3206 | t->answer_authenticated = authenticated; |
7aa8ce98 | 3207 | |
59c5b597 | 3208 | manager_dnssec_verdict(t->scope->manager, authenticated ? DNSSEC_SECURE : DNSSEC_INSECURE, t->key); |
72667f08 LP |
3209 | break; |
3210 | ||
105e1512 LP |
3211 | case DNSSEC_NSEC_OPTOUT: |
3212 | /* NSEC3 says the data might not be signed */ | |
202b76ae | 3213 | log_debug("Data is NSEC3 opt-out via NSEC/NSEC3 for transaction %u (%s)", t->id, key_str); |
019036a4 | 3214 | t->answer_dnssec_result = DNSSEC_UNSIGNED; |
105e1512 | 3215 | t->answer_authenticated = false; |
7aa8ce98 | 3216 | |
59c5b597 | 3217 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, t->key); |
105e1512 LP |
3218 | break; |
3219 | ||
72667f08 LP |
3220 | case DNSSEC_NSEC_NO_RR: |
3221 | /* No NSEC data? Bummer! */ | |
105e1512 LP |
3222 | |
3223 | r = dns_transaction_requires_nsec(t); | |
3224 | if (r < 0) | |
3225 | return r; | |
7aa8ce98 | 3226 | if (r > 0) { |
019036a4 | 3227 | t->answer_dnssec_result = DNSSEC_NO_SIGNATURE; |
59c5b597 | 3228 | manager_dnssec_verdict(t->scope->manager, DNSSEC_BOGUS, t->key); |
7aa8ce98 | 3229 | } else { |
019036a4 | 3230 | t->answer_dnssec_result = DNSSEC_UNSIGNED; |
105e1512 | 3231 | t->answer_authenticated = false; |
59c5b597 | 3232 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INSECURE, t->key); |
105e1512 LP |
3233 | } |
3234 | ||
3235 | break; | |
3236 | ||
3237 | case DNSSEC_NSEC_UNSUPPORTED_ALGORITHM: | |
3238 | /* We don't know the NSEC3 algorithm used? */ | |
019036a4 | 3239 | t->answer_dnssec_result = DNSSEC_UNSUPPORTED_ALGORITHM; |
59c5b597 | 3240 | manager_dnssec_verdict(t->scope->manager, DNSSEC_INDETERMINATE, t->key); |
72667f08 LP |
3241 | break; |
3242 | ||
3243 | case DNSSEC_NSEC_FOUND: | |
146035b3 | 3244 | case DNSSEC_NSEC_CNAME: |
72667f08 | 3245 | /* NSEC says it needs to be there, but we couldn't find it? Bummer! */ |
019036a4 | 3246 | t->answer_dnssec_result = DNSSEC_NSEC_MISMATCH; |
59c5b597 | 3247 | manager_dnssec_verdict(t->scope->manager, DNSSEC_BOGUS, t->key); |
72667f08 LP |
3248 | break; |
3249 | ||
3250 | default: | |
3251 | assert_not_reached("Unexpected NSEC result."); | |
3252 | } | |
3253 | } | |
3254 | ||
547973de LP |
3255 | return 1; |
3256 | } | |
3257 | ||
ec2c5e43 LP |
3258 | static const char* const dns_transaction_state_table[_DNS_TRANSACTION_STATE_MAX] = { |
3259 | [DNS_TRANSACTION_NULL] = "null", | |
3260 | [DNS_TRANSACTION_PENDING] = "pending", | |
547973de | 3261 | [DNS_TRANSACTION_VALIDATING] = "validating", |
3bbdc31d | 3262 | [DNS_TRANSACTION_RCODE_FAILURE] = "rcode-failure", |
ec2c5e43 LP |
3263 | [DNS_TRANSACTION_SUCCESS] = "success", |
3264 | [DNS_TRANSACTION_NO_SERVERS] = "no-servers", | |
3265 | [DNS_TRANSACTION_TIMEOUT] = "timeout", | |
3266 | [DNS_TRANSACTION_ATTEMPTS_MAX_REACHED] = "attempts-max-reached", | |
3267 | [DNS_TRANSACTION_INVALID_REPLY] = "invalid-reply", | |
7cc6ed7b | 3268 | [DNS_TRANSACTION_ERRNO] = "errno", |
ec2c5e43 | 3269 | [DNS_TRANSACTION_ABORTED] = "aborted", |
547973de | 3270 | [DNS_TRANSACTION_DNSSEC_FAILED] = "dnssec-failed", |
b2b796b8 | 3271 | [DNS_TRANSACTION_NO_TRUST_ANCHOR] = "no-trust-anchor", |
91adc4db | 3272 | [DNS_TRANSACTION_RR_TYPE_UNSUPPORTED] = "rr-type-unsupported", |
edbcc1fd | 3273 | [DNS_TRANSACTION_NETWORK_DOWN] = "network-down", |
0791110f | 3274 | [DNS_TRANSACTION_NOT_FOUND] = "not-found", |
ec2c5e43 LP |
3275 | }; |
3276 | DEFINE_STRING_TABLE_LOOKUP(dns_transaction_state, DnsTransactionState); | |
c3bc53e6 LP |
3277 | |
3278 | static const char* const dns_transaction_source_table[_DNS_TRANSACTION_SOURCE_MAX] = { | |
3279 | [DNS_TRANSACTION_NETWORK] = "network", | |
3280 | [DNS_TRANSACTION_CACHE] = "cache", | |
3281 | [DNS_TRANSACTION_ZONE] = "zone", | |
0d2cd476 | 3282 | [DNS_TRANSACTION_TRUST_ANCHOR] = "trust-anchor", |
c3bc53e6 LP |
3283 | }; |
3284 | DEFINE_STRING_TABLE_LOOKUP(dns_transaction_source, DnsTransactionSource); |